Increased Truebot Activity Infects U.S. and Canada Based Networks

SUMMARY

The Cybersecurity and Infrastructure Security Agency (CISA), the Federal Bureau of Investigation (FBI), the Multi-State Information Sharing and Analysis Center (MS-ISAC), and the Canadian Centre for Cyber Security (CCCS) are releasing this joint Cybersecurity Advisory (CSA) in response to cyber threat actors leveraging newly identified Truebot malware variants against organizations in the United States and Canada. As recently as May 31, 2023, the authoring organizations have observed an increase in cyber threat actors using new malware variants of Truebot (also known as Silence.Downloader). Truebot is a botnet that has been used by malicious cyber groups like CL0P Ransomware Gang to collect and exfiltrate information from its target victims.

Previous Truebot malware variants were primarily delivered by cyber threat actors via malicious phishing email attachments; however, newer versions allow cyber threat actors to also gain initial access through exploiting CVE-2022-31199—(a remote code execution vulnerability in the Netwrix Auditor application), enabling deployment of the malware at scale within the compromised environment. Based on confirmation from open-source reporting and analytical findings of Truebot variants, the authoring organizations assess cyber threat actors are leveraging both phishing campaigns with malicious redirect hyperlinks and CVE-2022-31199 to deliver new Truebot malware variants.

The authoring organizations recommend hunting for the malicious activity using the guidance outlined in this CSA, as well as applying vendor patches to Netwrix Auditor (version 10.5—see Mitigations section below).[1] Any organization identifying indicators of compromise (IOCs) within their environment should urgently apply the incident responses and mitigation measures detailed in this CSA and report the intrusion to CISA or the FBI.

Download the PDF version of this report:

AA23-187A Increased Truebot Activity Infects U.S. and Canada Based Networks (PDF, 891.26 KB )

Read the associated Malware Analysis Report MAR-10445155-1.v1 Truebot Activity Infects U.S. and Canada Based Networks or download the PDF version below:

MAR-10445155-1.v1 Truebot Activity Infects U.S. and Canada Based Networks (PDF, 315.39 KB )

For a downloadable copy of IOCs in .xml and .json format, see:

AA23-187A STIX XML (XML, 204.54 KB )

AA23-187A STIX JSON (JSON, 140.24 KB )

TECHNICAL DETAILS

Note: This advisory uses the MITRE ATT&CK® for Enterprise framework, version 13. See the MITRE ATT&CK Tactics and Techniques section below for cyber threat actors’ activity mapped to MITRE ATT&CK tactics and techniques.

Initial Access and Execution

In recent months, open source reporting has detailed an increase in Truebot malware infections, particularly cyber threat actors using new tactics, techniques, and procedures (TTPs), and delivery methods.[2] Based on the nature of observed Truebot operations, the primary objective of a Truebot infection is to exfiltrate sensitive data from the compromised host(s) for financial gain [TA0010].

• Phishing:
  • Cyber threat actors have historically used malicious phishing emails as the primary delivery method of Truebot malware, which tricks recipients into clicking a hyperlink to execute malware. Cyber threat actors have further been observed concealing email attachments (executables) as software update notifications [T1189] that appear to be legitimate [T1204.002], [T1566.002]. Following interaction with the executable, users will be redirected to a malicious web domain where script files are then executed. Note: Truebot malware can be hidden within various, legitimate file formats that are used for malicious purposes [T1036.008].[3]
• Exploitation of CVE-2022-31199:
  • Though phishing remains a prominent delivery method, cyber threat actors have shifted tactics, exploiting, in observable manner, a remote code execution vulnerability (CVE-2022-31199) in Netwrix Auditor [T1190]—software used for on-premises and cloud-based IT system auditing. Through exploitation of this CVE, cyber threat actors gain initial access, as well as the ability to move laterally within the compromised network [T1210].

Figure 1: CVE-2022-31199 Delivery Method for Truebot

Following the successful download of the malicous file, Truebot renames itself and then loads FlawedGrace onto the host. Please see the FlawedGrace section below for more information on how this remote access tool (RAT) is used in Truebot operations.

After deployment by Truebot, FlawedGrace is able to modify registry [T1112] and print spooler programs [T1547.012] that control the order that documents are loaded to a print queue. FlawedGrace manipulates these features to both escalate privilege and establish persistence.

During FlawedGrace’s execution phase, the RAT stores encrypted payloads [T1027.009] within the registry. The tool can create scheduled tasks and inject payloads into msiexec[.]exe and svchost[.]exe, which are command processes that enable FlawedGrace to establish a command and control (C2) connection to 92.118.36[.]199, for example, as well as load dynamic link libraries (DLLs) [T1055.001] to accomplish privilege escalation.

Several hours post initial access, Truebot has been observed injecting Cobalt Strike beacons into memory [T1055] in a dormant mode for the first few hours prior to initiating additional operations. Please see the Cobalt Strike section below for more information on how this remote access tool (RAT) is used in Truebot operations.

Discovery and Defense Evasion

During the first stage of Truebot’s execution process, it checks the current version of the operating system (OS) with RtlGetVersion and processor architecture using GetNativeSystemInfo [T1082].[4] Note: This variant of Truebot malware is designed with over one gigabyte (GB) of junk code which functions to hinder detection and analysis efforts [T1027.001].

Following the initial checks for system information, Truebot has the capability to enumerate all running processes [T1057], collect sensitive local host data [T1005], and send this data to an encoded data string described below for second-stage execution. Based on IOCs in table 1, Truebot also has the ability to discover software security protocols and system time metrics, which aids in defense evasion, as well as enables synchronization with the compromised system’s internal clock to facilitate scheduling tasks [T1518.001][T1124].

Next, it uses a .JSONIP extension, (e.g., IgtyXEQuCEvAM.JSONIP), to create a thirteen character globally unique identifier (GUID)—a 128-bit text string that Truebot uses to label and organize the data it collects [T1036].

After creating the GUID, Truebot compiles and enumerates running process data into either a base64 or unique hexadecimal encoded string [T1027.001]. Truebot’s main goal is identifying the presence of security debugger tools. However, the presence of identified debugger tools does not change Truebot’s execution process—the data is compiled into a base64 encoded string for tracking and defense evasion purposes [T1082][T1622].

Data Collection and Exfiltration

Following Truebot’s enumeration of running processes and tools, the affected system’s computer and domain name [T1082][T1016], along with the newly generated GUID, are sent to a hard-coded URL in a POST request (as observed in the user-agent string). Note: A user-agent string is a customized HTTP request that includes specific device information required for interaction with web content. In this instance, cyber threat actors can redirect victims to malicious domains and further establish a C2 connection.

The POST request functions as means for establishing a C2 connection for bi-lateral communication. With this established connection, Truebot uses a second obfuscated domain to receive additional payloads [T1105], self-replicate across the environment [T1570], and/or delete files used in its operations [T1070.004]. Truebot malware has the capability to download additional malicious modules [T1105], load shell code [T1620], and deploy various tools to stealthily navigate an infected network.

Associated Delivery Vectors and Tools

Truebot has been observed in association with the following delivery vectors and tools:

Raspberry Robin (Malware)

Raspberry Robin is a wormable malware with links to other malware families and various infection methods, including installation via USB drive [T1091].[5] Raspberry Robin has evolved into one of the largest malware distribution platforms and has been observed deploying Truebot, as well as other post-compromise payloads such as IcedID and Bumblebee malware.[6] With the recent shift in Truebot delivery methods from malicious emails to the exploitation of CVE-2022-31199, a large number of Raspberry Robin infections have leveraged this exploitable CVE.[2]

Flawed Grace (Malware)

FlawedGrace is a remote access tool (RAT) that can receive incoming commands [T1059] from a C2 server sent over a custom binary protocol [T1095] using port 443 to deploy additional tools [T1105].[7] Truebot malware has been observed leveraging (and dropping) FlawedGrace via phishing campaigns as an additional payload [T1566.002].[8] Note: FlawedGrace is typically deployed minutes after Truebot malware is executed.

Cobalt Strike (Tool)

Cobalt Strike is a popular remote access tool (RAT) that cyber threat actors have leveraged—in an observable manner—for a variety of post-exploitation means. Typically a few hours after Truebot’s execution phase, cyber threat actors have been observed deploying additional payloads containing Cobalt Strike beacons for persistence and data exfiltration purposes [T1059].[2] Cyber threat actors use Cobalt Strike to move laterally via remote service session hijacking [T1563.001][T1563.002], collecting valid credentials through LSASS memory credential dumping, or creating local admin accounts to achieve pass the hash alternate authentication [T1003.001][T1550.002].

Teleport (Tool)

Cyber threat actors have been observed using a custom data exfiltration tool, which Talos has named “Teleport.”[2] Teleport is known to evade detection during data exfiltration by using an encryption key hardcoded in the binary and a custom communication protocol [T1095] that encrypts data using advanced encryption standard (AES) and a hardcoded key [T1048][T1573.002]. Furthermore, to maintain its stealth, Teleport limits the data it collects and syncs with outbound organizational data/network traffic [T1029][T1030].

Truebot Malware Indicators of Compromise (IOCs)

Truebot IOCs from May 31, 2023, contain IOCs from cyber threat actors conducting Truebot malspam campaigns. Information is derived from a trusted third party, they observed cyber threat actors from 193.3.19[.]173 (Russia) using a compromised local account to conduct phishing campaigns on May 23, 2023 and spread malware through: https[:]//snowboardspecs[.]com/nae9v, which then promptly redirects the user to: https://www.meditimespharma[.]com/gfghthq/, which a trusted third party has linked to other trending Truebot activity.

After redirecting to https://www.meditimespharma[.]com/gfghthq/, trusted third parties have observed, the cyber threat actors using Truebot to pivot to https://corporacionhardsoft[.]com/images/2/Document_16654.exe, which is a domain associated with snowboardspecs[.]com. This malicious domain has been linked to UNC4509, a threat cluster that has been known to use traffic distribution systems (TDS) to redirect users to either a benign or malicious website to facilitate their malicious phishing campaigns in May 2023.

According to trusted third parties, the MD5 Hash: 6164e9d297d29aa8682971259da06848 is downloaded from https://corporacionhardsoft.com/images/2/Document_16654[.]exe, and has been flagged by numerous security vendors, as well as is linked to UNC4509 Truebot campaigns. Note: These IOCs are associated with Truebot campaigns used by Graceful Spider to deliver FlawedGrace and LummaStealer payloads in May of 2023.

After Truebot is downloaded, the malware copies itself to C:\Intel\RuntimeBroker.exe and—based on trusted third party analysis—links to https://essadonio.com/538332[.]php (which is linked to 45.182.189[.]71 (Panama) and is associated with other trending Truebot malware campaigns from May 2023).

Please reference table 1 for IOCs described in the paragraph above.

Table1: Truebot IOCs from May of 2023 | |
—|—|—

Indicator Type

|

Indicator

|

Source

Registrant

|

GKG[.]NET Domain Proxy Service Administrator

|

Trusted Third Party

Compromised Account Created:

|

2022-04-10

|

Trusted Third Party

Malicious account created

|

1999-11-09

|

Trusted Third Party

IP

|

193.3.19[.]173 (Russia)

|

Trusted Third Party

URL

|

https://snowboardspecs[.]com/nae9v

|

Trusted Third Party

Domain

|

https://corporacionhardsoft[.]com/images/2/Document_16654.exe

|

Trusted Third Party

File

|

Document_16654[.]exe

|

Trusted Third Party

MD5 Hash

|

6164e9d297d29aa8682971259da06848

|

Trusted Third Party

File

|

Document_may_24_16654[.]exe

|

Trusted Third Party

File

|

C:\Intel\RuntimeBroker[.]exe

|

Trusted Third Party

URL

|

https://essadonio.com/538332[.]php

|

Trusted Third Party

IP

|

45.182.189[.]71 (Panama)

|

Trusted Third Party

Account Created

|

2023-05-18

|

Trusted Third Party

Table 2: Truebot malware IOCs from May of 2023 | |
—|—|—

Indicator Type

|

Indicator

|

Source

File Name

|

Secretsdump[.]py

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

Domain

|

Imsagentes[.]pe

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

URL

|

https://imsagentes[.]pe/dgrjfj/

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

URL

|

https://imsagentes[.]pe/dgrjfj

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

URL

|

https://hrcbishtek[.]com/{5

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

URL

|

https://ecorfan.org/base/sj/document_may_24_16654[.]exe

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

Domain

|

Hrcbishtek[.]com

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

MD5 Hash

|

F33734DFBBFF29F68BCDE052E523C287

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

MD5 Hash

|

F176BA63B4D68E576B5BA345BEC2C7B7

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

MD5 Hash

|

F14F2862EE2DF5D0F63A88B60C8EEE56

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

Domain

|

Essadonio[.]com

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

Domain

|

Ecorfan[.]org

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

SHA256 Hash

|

C92C158D7C37FEA795114FA6491FE5F145AD2F8C08776B18AE79DB811E8E36A3

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

File Name

|

Atexec[.]py

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

MD5 Hash

|

A0E9F5D64349FB13191BC781F81F42E1

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

IPv4

|

92.118.36[.]199

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

IPv4

|

81.19.135[.]30

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

MD5 Hash

|

72A589DA586844D7F0818CE684948EEA

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

SHA256 Hash

|

717BEEDCD2431785A0F59D194E47970E9544FBF398D462A305F6AD9A1B1100CB

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

IPv4

|

5.188.86[.]18

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

IPv4

|

5.188.206[.]78

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

IPv4

|

45.182.189[.]71

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

IPv4

|

139.60.160[.]166

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

SHA256 Hash

|

121A1F64FFF22C4BFCEF3F11A23956ED403CDEB9BDB803F9C42763087BD6D94E

|

https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/

Table 3: Truebot IOCs from May 2023 (Malicious Domains, and Associated IP addresses and URLs) | |
—|—|—
Malicious Domain |Associated IP(s)|Beacon URL

nitutdra[.]com

|

46.161.40[.]128

|

romidonionhhgtt[.]com

|

46.161.40.128

|

midnigthwaall[.]com

|

46.161.40[.]128

|

dragonetzone[.]com

|

46.161.40[.]128

|

hxxps://dragonetzone[.]com/gate_info[.]php

rprotecruuio[.]com

|

45.182.189[.]71

|

essadonio[.]com

|

45.182.189[.]71

|

hxxps://nomoresense[.]com/checkinfo[.]php

nomoresense[.]com

|

45.182.189[.]91

|

hxxps://nomoresense[.]com/checkinfo[.]php

ronoliffuion[.]com

|

45.182.189[.]120

|

hxxps://ronoliffuion[.]com/dns[.]php

bluespiredice[.]com

|

45.182.189[.]119

|

dremmfyttrred[.]com

|

45.182.189[.]103

|

hxxps://dremmfyttrred[.]com/dns[.]php

ms-online-store[.]com

|

45.227.253[.]102

|

ber6vjyb[.]com

|

92.118.36[.]252

|

hxxps://ber6vjyb[.]com/dns[.]php

jirostrogud[.]com

|

88.214.27[.]101

|

hxxps://ber6vjyb[.]com/dns[.]php

fuanshizmo[.]com

|

45.182.189[.]229

|

qweastradoc[.]com

|

92.118.36[.]213

|

hxxp://nefosferta[.]com/gate[.]php

qweastradoc[.]com

|

92.118.36[.]213

|

hxxp://nefosferta[.]com/gate[.]php

qweastradoc[.]com

|

92.118.36[.]213

|

hxxp://nefosferta[.]com/gate[.]php

hiperfdhaus[.]com

|

88.214.27[.]100

|

hxxp://nefosferta[.]com/gate[.]php

guerdofest[.]com

|

45.182.189[.]228

|

hxxp://qweastradoc[.]com/gate[.]php

nefosferta[.]com

|

179.60.150[.]139

|

hxxp://nefosferta[.]com/gate[.]php

_Table ****4: Truebot IOCs from May 2023 Continued (_Malicious Domains and Associated Hashes) | | |
—|—|—|—

** Malicious Domain**

|

MD5

|

SHA1

|

SHA256

nitutdra[.]com

|

|

|

romidonionhhgtt[.]com

|

|

|

midnigthwaall[.]com

|

|

|

dragonetzone[.]com

|

64b27d2a6a55768506a5658a31c045de

|

c69f080180430ebf15f984be14fb4c76471cd476

|

e0178ab0893a4f25c68ded11e74ad90403443e413413501d138e0b08a910471e

rprotecruuio[.]com

|

|

|

essadonio[.]com

|

9a3bad7d8516216695887acc9668cda1

|

a89c097138e5aab1f35b9a03900600057d907690

|

4862618fcf15ba4ad15df35a8dcb0bdb79647b455fea6c6937c7d050815494b0

essadonio[.]com

|

6164e9d297d29aa8682971259da06848

|

96b95edc1a917912a3181d5105fd5bfad1344de0

|

717beedcd2431785a0f59d194e47970e9544fbf398d462a305f6ad9a1b1100cb

nomoresense[.]com

|

8f924f3cbe5d8fe3ecb7293478901f1a

|

516051b4cab1be74d32a6c446eabac7fc354904f

|

6b646641c823414c2ee30ae8b91be3421e4f13fa98e2d99272956e61eecfc5a1

nomoresense[.]com

|

ac6a2f1eafaae9f6598390d1017dd76c

|

1c637c2ded5d3a13fd9b56c35acf4443f308be52

|

f9f649cb5de27f720d58aa44aec6d0419e3e89f453730e155067506ad3ece638

ronoliffuion[.]com

|

881485ac77859cf5aaa8e0d64fbafc5f

|

51be660a3bdaab6843676e9d3b2af8444e88bbda

|

36d89f0455c95f9b00a8cea843003d0b53c4e33431fe57b5e6ec14a6c2e00e99

bluespiredice[.]com

|

|

|

dremmfyttrred[.]com

|

e4a42cbda39a20134d6edcf9f03c44ed

|

afda13d5365b290f7cdea701d00d05b0c60916f8

|

47f962063b42de277cd8d22550ae47b1787a39aa6f537c5408a59b5b76ed0464

dremmfyttrred[.]com

|

aa949d1a7ebe5f878023c6cfb446e29b

|

06057d773ad04fda177f6b0f6698ddaa47f7168a

|

594ade1fb42e93e64afc96f13824b3dbd942a2cdbc877a7006c248a38425bbc1

dremmfyttrred[.]com

|

338476c2b0de4ee2f3e402f3495d0578

|

03916123864aa034f7ca3b9d45b2e39b5c91c502

|

a67df0a8b32bdc5f9d224db118b3153f66518737e702314873b673c914b2bb5c

ms-online-store[.]com

|

|

|

ber6vjyb[.]com

|

46fe07c07fd0f45ba45240ef9aae2a44

|

b918f97c7c6ebc9594de3c8f2d9d75ecc292d02b

|

c0f8aeeb2d11c6e751ee87c40ee609aceb1c1036706a5af0d3d78738b6cc4125

jirostrogud[.]com

|

89c8afc5bbd34f160d8a2b7218b9ca4a

|

16ecf30ff8c7887037a17a3eaffcb17145b69160

|

5cc8c9f2c9cee543ebac306951e30e63eff3ee103c62dadcd2ce43ef68bc7487

jirostrogud[.]com

|

5da364a8efab6370a174736705645a52

|

792623e143ddd49c36f6868e948febb0c9e19cd3

|

80b9c5ec798e7bbd71bbdfffab11653f36a7a30e51de3a72c5213eafe65965d9

fuanshizmo[.]com

|

|

|

qweastradoc[.]com

|

ee1ccb6a0e38bf95e44b73c3c46268c5

|

62f5a16d1ef20064dd78f5d934c84d474aca8bbe

|

0e3a14638456f4451fe8d76fdc04e591fba942c2f16da31857ca66293a58a4c3

qweastradoc[.]com

|

82d4025b84cf569ec82d21918d641540

|

bb32c940f9ca06e7e8533b1d315545c3294ee1a0

|

c042ad2947caf4449295a51f9d640d722b5a6ec6957523ebf68cddb87ef3545c

qweastradoc[.]com

|

dbecfe9d5421d319534e0bfa5a6ac162

|

9e7a2464f53ce74d840eb84077472bc29fd1ba05

|

c9b874d54c18e895face055eeb6faa2da7965a336d70303d0bd6047bec27a29d

qweastradoc[.]com

|

b7fed593e8eb3646f876367b56725e6c

|

44090a7858eceb28bc111e1edd2f0dc98047afb2

|

ff8c8c8bfba5f2ba2f8003255949678df209dbff95e16f2f3c338cfa0fd1b885

hiperfdhaus[.]com

|

8e2b823aac6c9e11fcabecb1d8c19adf

|

77ad34334a370d85ca5e77436ed99f18b185eee3

|

a30e1f87b78d1cd529fbe2afdd679c8241d3baab175b2f083740263911a85304

hiperfdhaus[.]com

|

8a94163ddf956abd0ea92d89db0034e5

|

abc96032071adeb6217f0a5ba1aff55dc11f5438

|

b95a764820e918f42b664f3c9a96141e2d7d7d228da0edf151617fabdd9166cf

guerdofest[.]com

|

65fb9572171b903aa31a325f550d8778

|

d8bd44b7a8f136e29b31226f4edf566a4223266c

|

d5bbcaa0c3eeea17f12a5cc3dbcaffff423d00562acb694561841bcfe984a3b7

nefosferta[.]com

|

d9d85bdb6a3ac60a8ba6776c661dbace

|

78e38e522b1765efb15d0585e13c1f1301e90788

|

092910024190a2521f21658be849c4ac9ae6fa4d5f2ecd44c9055cc353a26875

nefosferta[.]com

|

20643549f19bed9a6853810262622755

|

c8227dcc1cd6ecc684de8c5ea9b16e3b35f613f1

|

1ef8cdbd3773bd82e5be25d4ba61e5e59371c6331726842107c0f1eb7d4d1f49

nefosferta[.]com

|

e9299fc9b7daa0742c28bfc4b03b7b25

|

77360abc473dc65c8bdd73b6459b9ea8fddb6f1d

|

22e3f4602a258e92a0b8deb5a2bd69c67f4ac3ca67362a745178848a9da7a3cc

nefosferta[.]com

|

775fb391db27e299af08933917a3acda

|

eaaa5e68956a3a3f6113e965199f479e10ae9956

|

2d50b03a92445ba53ae147d0b97c494858c86a56fe037c44bc0edabb902420f7

nefosferta[.]com

|

f4045710c99d347fe6dfa2c0fcadde29

|

b7bffdbbaf817d149bbd061070a2d171449afbfc

|

32ae88cddeeeec255d6d9c827f6bffc7a95e9ea7b83a84a79ff793735a4b4ed7

nefosferta[.]com

|

587acecdb9491e0897d1067eb02e7c8d

|

a9eb1ac4b85d17da3a2bae5835c7e862d481c189

|

55d1480cd023b74f10692c689b56e7fd6cc8139fb6322762181daead55a62b9e

nefosferta[.]com

|

0bae65245e5423147fce079de29b6136

|

f24232330e6f428bfbb6b9d8154db1c4046c2fc2

|

6210a9f5a5e1dc27e68ecd61c092d2667609e318a95b5dade3c28f5634a89727

nefosferta[.]com

|

5022a85b39a75ebe2bc0411d7b058b2e

|

a9040ac0e9f482454e040e2a7d874ddc50e6f6ce

|

68a86858b4638b43d63e8e2aaec15a9ebd8fc14d460dd74463db42e59c4c6f89

nefosferta[.]com

|

6a2f114a8995dbeb91f766ac2390086e

|

edac3cf9533b6f7102f6324fadb437a0814cc680

|

72813522a065e106ac10aa96e835c47aa9f34e981db20fa46a8f36c4543bb85d

nefosferta[.]com

|

e9115cc3280c16f9019e0054e059f4b8

|

dad01b0c745649c6c8b87dbeb7ab549ed039515d

|

7a64bc69b60e3cd3fd00d4424b411394465640f499e56563447fe70579ccdd00

nefosferta[.]com

|

b54cc9a3dd88e478ea601dfd5b36805e

|

318fdfec4575d1530a41c80274aa8caae7b7f631

|

7c607eca4005ba6415e09135ef38033bb0b0e0ff3e46d60253fc420af7519347

nefosferta[.]com

|

f129c12b1bda7426f6b31682b42ee4b0

|

5bb804153029c97fe23517ae5428a591c3c63f28

|

7c79ec3f5c1a280ffdf19d0000b4bfe458a3b9380c152c1e130a89de3fe04b63

nefosferta[.]com

|

f68aa4c92dd30bd5418f136aaf6c07d6

|

aa56f43e39d114235a6b1d5f66b593cc80325fa4

|

7e39dcd15307e7de862b9b42bf556f2836bf7916faab0604a052c82c19e306ca

nefosferta[.]com

|

acac995cee8a6a75fa79eb41bdffa53f

|

971a00a392b99f64a3886f40b6ef991e62f0fe2f

|

97bae3587f1d2fd35f24eb214b9dd6eed95744bed62468d998c7ef55ff8726d4

nefosferta[.]com

|

36057710279d9f0d023cb5613aa76d5e

|

e4dd1f8fc4e44c8fd0e25242d994c4b59eed6939

|

97d0844ce9928e32b11706e06bf2c4426204d998cb39964dd3c3de6c5223fff0

nefosferta[.]com

|

37e6904d84153d1435407f4669135134

|

1dcd85f7364ea06cd595a86e3e9be48995d596e9

|

bf3c7f0ba324c96c9a9bff6cf21650a4b78edbc0076c68a9a125ebcba0e523c9

nefosferta[.]com

|

4f3916e7714f2a32402c9d0b328a2c91

|

87a692e3592f7b997c7d962919e243b665f2be36

|

c3743a8c944f5c9b17528418bf49b153b978946838f56e5fca0a3f6914bee887

nefosferta[.]com

|

d9daaa0df32b0bb01a09e500fc7f5881

|

f9cb839adba612db5884e1378474996b4436c0cd

|

c3b3640ddf53b26f4ebd4eedf929540edb452c413ca54d0d21cc405c7263f490

nefosferta[.]com

|

c87fb9b9f6c343670bed605420583418

|

f05cf0b026b2716927dac8bcd26a2719ea328964

|

c6c4f690f0d15b96034b4258bdfaf797432a3ec4f73fbc920384d27903143cb0

nefosferta[.]com

|

2be64efd0fa7739123b26e4b70e53c5c

|

318fdfec4575d1530a41c80274aa8caae7b7f631

|

ed38c454575879c2546e5fccace0b16a701c403dfe3c3833730d23b32e41f2fe

Table ****5: Truebot IOCs Connected to Russia, and Panama Locations | | |
—|—|—|—

** Malicious Domain**

|

IP Addresses

|

Files

|

SHA256

Dremmfyttrred[.]com

|

|

|

|

45.182.189[.]103

|

|

|

94.142.138[.]61

|

|

|

172.64.155[.]188

|

|

|

104.18.32[.]68

|

|

|

|

Update[.]exe

|

|

|

Document_26_apr_2443807[.]exe

|

|

|

3ujwy2rz7v[.]exe

|

|

|

|

fe746402c74ac329231ae1b5dffa8229b509f4c15a0f5085617f14f0c1579040

droogggdhfhf[.]com

|

|

3LXJyA6Gf[.]exe

|

7d75244449fb5c25d8f196a43a6eb9e453652b2185392376e7d44c21bd8431e7

MITRE ATT&CK TACTICS AND TECHNIQUES

See Tables 6-16 for all referenced cyber threat actor tactics and techniques for enterprise environments in this advisory. For assistance with mapping malicious cyber activity to the MITRE ATT&CK framework, see CISA and MITRE ATT&CK’s Best Practices for MITRE ATT&CK Mapping and CISA’s Decider Tool.

Table 6: Initial Access | |
—|—|—

Technique Title

|

ID

|

Use

Replication Through Removable Media

|

T1091

|

Cyber threat actors use removable media drives to deploy Raspberry Robin malware.

Drive-by Compromise

|

T1189

|

Cyber threat actors embed malicious links or attachments within web domains to gain initial access.

Exploit Public-Facing Application

|

T1190

|

Cyber threat actors are exploiting Netwrix vulnerability CVE-2022-31199 for initial access with follow-on capabilities of lateral movement through remote code execution.

Phishing

|

T1566.002

|

Truebot actors can send spear phishing links to gain initial access.

Table 7: Execution | |
—|—|—

Technique Title

|

ID

|

Use

Command and Scripting Interpreter

|

T1059

|

Cyber threat actors have been observed dropping cobalt strike beacons as a reverse shell proxy to create persistence within the compromised network.

Cyber threat actors use FlawedGrace to receive PowerShell commands over a C2 channel to deploy additional tools.

Shared Modules

|

T1129

|

Cyber threat actors can deploy malicious payloads through obfuscated share modules.

User Execution: Malicious Link

|

T1204.001

|

Cyber threat actors trick users into clicking a link by making them believe they need to perform a Google Chrome software update.

Table 8: Persistence | |
—|—|—

Technique Title

|

ID

|

Use

Hijack Execution Flow: DLL Side-Loading

|

1574.002

|

Cyber threat actors use Raspberry Robin, among other toolsets to side-load DLLs to maintain persistence.

Table 9: Privilege Escalation | |
—|—|—

Technique Title

|

ID

|

Use

Boot or Logon Autostart Execution: Print Processors

|

T1547.012

|

FlawedGrace malware manipulates print spooler functions to achieve privilege escalation.

Table 10: Defense Evasion | |
—|—|—

Technique Title

|

ID

|

Use

Obfuscated Files or Information

|

T1027

|

Truebot uses a .JSONIP extension (e.g., IgtyXEQuCEvAM.JSONIP), to create a GUID.

Obfuscated Files or Information: Binary Padding

|

T1027.001

|

Cyber threat actors embed around one gigabyte of junk code within the malware string to evade detection protocols.

Masquerading: Masquerade File Type

|

T1036.008

|

Cyber threat actors hide Truebot malware as legitimate appearing file formats.

Process Injection

|

T1055

|

Truebot malware has the ability to load shell code after establishing a C2 connection.

Indicator Removal: File Deletion

|

T1070.004

|

Truebot malware implements self-deletion TTPs throughout its attack cycle to evade detection.

Teleport exfiltration tool deletes itself after it has completed exfiltrating data to the C2 station.

Modify Registry

|

T1112

|

FlawedGrace is able to modify registry programs that control the order that documents are loaded to a print que.

Reflective Code Loading

|

T1620

|

Truebot malware has the capability to load shell code and deploy various tools to stealthily navigate an infected network.

Table 11: Credential Access | |
—|—|—

Technique Title

|

ID

|

Use

OS Credential Dumping: LSASS Memory

|

T1003.001

|

Cyber threat actors use cobalt strike to gain valid credentials through LSASS memory dumping.

Table 12: Discovery | |
—|—|—

Technique Title

|

ID

|

Use

System Network Configuration Discovery

|

T1016

|

Truebot malware scans and enumerates the affected system’s domain names.

Process Discovery

|

T1057

|

Truebot malware enumerates all running processes on the local host.

System Information Discovery

|

T1082

|

Truebot malware scans and enumerates the OS version information, and processor architecture.

Truebot malware enumerates the affected system’s computer names.

System Time Discovery

|

T1124

|

Truebot has the ability to discover system time metrics, which aids in enables synchronization with the compromised system’s internal clock to facilitate scheduling tasks.

Software Discovery: Security Software Discovery

|

T1518.001

|

Truebot has the ability to discover software security protocols, which aids in defense evasion.

Debugger Evasion

|

T1622

|

Truebot malware scans the compromised environment for debugger tools and enumerates them in effort to evade network defenses.

Table 13: Lateral Movement | |
—|—|—

Technique Title

|

ID

|

Use

Exploitation of Remote Services

|

T1210

|

Cyber threat actors exploit CVE-2022-31199 Netwrix Auditor vulnerability and use its capabilities to move laterally within a compromised network.

Use Alternate Authentication Material: Pass the Hash

|

T1550.002

|

Cyber threat actors use cobalt strike to authenticate valid accounts

Remote Service Session Hijacking

|

T1563.001

|

Cyber threat actors use cobalt strike to hijack remote sessions using SSH and RDP hijacking methods.

Remote Service Session Hijacking: RDP Hijacking

|

T1563.002

|

Cyber threat actors use cobalt strike to hijack remote sessions using SSH and RDP hijacking methods.

Lateral Tool Transfer

|

T1570

|

Cyber threat actors deploy additional payloads to transfer toolsets and move laterally.

Table 14: Collection | |
—|—|—

Technique Title

|

ID

|

Use

Data from Local System

|

T1005

|

Truebot malware checks the current version of the OS and the processor architecture and compiles the information it receives.

Truebot gathers and compiles compromised system’s host and domain names.

Screen Capture

|

T1113

|

Truebot malware takes snapshots of local host data, specifically processor architecture data, and sends that to a phase 2 encoded data string.

Table 15: Command and Control | |
—|—|—

Technique Title

|

ID

|

Use

Application Layer Protocol

|

T1071

|

Cyber threat actors use teleport exfiltration tool to blend exfiltrated data with network traffic.

Non-Application Protocol

|

T1095

|

Cyber threat actors use Teleport and FlawedGrace to send data over custom communication protocol.

Ingress Transfer Tool

|

T1105

|

Cyber threat actors deploy various ingress transfer tool payloads to move laterally and establish C2 connections.

Encrypted Channel: Asymmetric Cryptography

|

T1573.002

|

Cyber threat actors use Teleport to create an encrypted channel using AES.

Table 16: Exfiltration | |
—|—|—

Technique Title

|

ID

|

Use

Scheduled Transfer

|

T1029

|

Teleport limits the data it collects and syncs with outbound organizational data/network traffic.

Data Transfer Size Limits

|

T1030

|

Teleport limits the data it collects and syncs with outbound organizational data/network traffic.

Exfiltration Over C2 Channel

|

T1048

|

Cyber threat actors blend exfiltrated data with network traffic to evade detection.

Cyber threat actors use the Teleport tool to exfiltrate data over a C2 protocol.

DETECTION METHODS

CISA and authoring organizations recommend that organizations review and implement the following detection signatures, along with: Win/malicious_confidence100% (W), Trojan:Win32/Tnega!MSR, and Trojan.Agent.Truebot.Gen, as well as YARA rules below to help detect Truebot malware.

Detection Signatures

Figure 2: Snort Signature to Detect Truebot Malware

alert tcp any any -> any any (msg:”TRUEBOT: Client HTTP Header”; sid:x; rev:1; flow:established,to_server; content:”Mozilla/112.0 (compatible|3b 20 4d 53 49 45 20 31 31 2e 30 3b 20 57 69 6e 64 6f 77 73 20 4e 54 20 31 30 2e 30 30 29|”; http_header; nocase; classtype:http-header; metadata:service http;)

---

YARA Rules

CISA developed the following YARA to aid in detecting the presence of Truebot Malware.

Figure 3: YARA Rule for Detecting Truebot Malware

rule CISA_10445155_01 : TRUEBOT downloader

{

meta:

Author = "CISA Code & Media Analysis"

Incident = "10445155"

Date = "2023-05-17"

Last_Modified = "20230523_1500"

Actor = "n/a"

Family = "TRUEBOT"

Capabilities = "n/a"

Malware_Type = "downloader"

Tool_Type = "n/a"

Description = "Detects TRUEBOT downloader samples"

SHA256 = "7d75244449fb5c25d8f196a43a6eb9e453652b2185392376e7d44c21bd8431e7"

strings:

$s1 = { 64 72 65 6d 6d 66 79 74 74 72 72 65 64 2e 63 6f 6d }

$s2 = { 4e 73 75 32 4f 64 69 77 6f 64 4f 73 32 }

$s3 = { 59 69 50 75 6d 79 62 6f 73 61 57 69 57 65 78 79 }

$s4 = { 72 65 70 6f 74 73 5f 65 72 72 6f 72 2e 74 78 74 }

$s5 = { 4c 6b 6a 64 73 6c 66 6a 33 32 6f 69 6a 72 66 65 77 67 77 2e 6d 70 34 }

$s6 = { 54 00 72 00 69 00 67 00 67 00 65 00 72 00 31 00 32 }

$s7 = { 54 00 55 00 72 00 66 00 57 00 65 00 73 00 54 00 69 00 66 00 73 00 66 }

condition:

5 of them

}

---

• Additional YARA rules for detecting Truebot malware can be referenced from GitHub.[9]

INCIDENT RESPONSE

The following steps are recommended if organizations detect a Truebot malware infection and compromise:

1. Quarantine or take offline potentially affected hosts.
2. Collect and review artifacts such as running processes/services, unusual authentications, and recent network connections.
3. Provision new account credentials.
4. Reimage compromised host.
5. Report the compromise to CISA via CISA’s 24/7 Operations Center ([email protected] or 888-282-0870) or contact your local FBI field office. State, local, tribal, or territorial government entities can also report to MS-ISAC ([email protected] or 866-787-4722).

MITIGATIONS

CISA and the authoring organizations recommend organizations implement the below mitigations, including mandating phishing-resistant multifactor authentication (MFA) for all staff and services.

For additional best practices, see CISA’s Cross-Sector Cybersecurity Performance Goals (CPGs). The CPGs, developed by CISA and the National Institute of Standards and Technology (NIST), are a prioritized subset of IT and OT security practices that can meaningfully reduce the likelihood and impact of known cyber risks and common TTPs. Because the CPGs are a subset of best practices, CISA and co-sealers recommend software manufacturers implement a comprehensive information security program based on a recognized framework, such as the NIST Cybersecurity Framework (CSF).

• Apply patches to CVE-2022-31199
• Update Netwrix Auditor to version 10.5

Netwrix recommends using their Auditor application only on internally facing networks. System owners that don’t follow this recommendation, and use the application in externally facing instances, are at increased risk to having CVE-2022-31199 exploited on their systems.

Reduce threat of malicious actors using remote access tools by:

• Implementing application controls to manage and control execution of software, including allowlisting remote access programs.
  • Application controls should prevent installation and execution of portable versions of unauthorized remote access and other software. A properly configured application allowlisting solution will block any unlisted application execution. Allowlisting is important because antivirus solutions may fail to detect the execution of malicious portable executables when the files use any combination of compression, encryption, or obfuscation.

See the National Security Agency’s Cybersecurity Information sheet, Enforce Signed Software Execution Policies, and additional guidance below:

• Strictly limit the use of RDP and other remote desktop services. If RDP is necessary, rigorously apply best practices, for example [CPG 2.W]:
  • Audit the network for systems using RDP.
  • Close unused RDP ports.
  • Enforce account lockouts after a specified number of attempts.
  • Apply phishing-resistant multifactor authentication (MFA).
  • Log RDP login attempts.
• Disable command-line and scripting activities and permissions [CPG 2.N].
• Restrict the use of PowerShell by using Group Policy, and only grant to specific users on a case-by-case basis. Typically, only those users or administrators who manage the network or Windows operating systems (OSs) should be permitted to use PowerShell [CPG 2.E].
• Update Windows PowerShell or PowerShell Core to the latest version and uninstall all earlier PowerShell versions. Logs from Windows PowerShell prior to version 5.0 are either non-existent or do not record enough detail to aid in enterprise monitoring and incident response activities [CPG 1.E, 2.S, 2.T].
• Enable enhanced PowerShell logging [CPG 2.T, 2.U].
  • PowerShell logs contain valuable data, including historical OS and registry interaction and possible IOCs of a cyber threat actor’s PowerShell use.
  • Ensure PowerShell instances, using the latest version, have module, script block, and transcription logging enabled (enhanced logging).
  • The two logs that record PowerShell activity are the PowerShell Windows Event Log and the PowerShell Operational Log. The authoring organizations recommend turning on these two Windows Event Logs with a retention period of at least 180 days. These logs should be checked on a regular basis to confirm whether the log data has been deleted or logging has been turned off. Set the storage size permitted for both logs to as large as possible.
• Configure the Windows Registry to require User Account Control (UAC) approval for any PsExec operations requiring administrator privileges to reduce the risk of lateral movement by PsExec.
• Review domain controllers, servers, workstations, and active directories for new and/or unrecognized accounts [CPG 4.C].
• Audit user accounts with administrative privileges and configure access controls according to the principle of least privilege (PoLP) [CPG 2.E].
• Reduce the threat of credential compromise via the following:
  • Place domain admin accounts in the protected users’ group to prevent caching of password hashes locally.
  • Implement Credential Guard for Windows 10 and Server 2016 (Refer to Microsoft: Manage Windows Defender Credential Guard for more information). For Windows Server 2012R2, enable Protected Process Light for Local Security Authority (LSA).
  • Refrain from storing plaintext credentials in scripts.
• Implement time-based access for accounts set at the admin level and higher [CPG 2.A, 2.E]. For example, the Just-in-Time (JIT) access method provisions privileged access when needed and can support enforcement of the principle of least privilege (as well as the Zero Trust model). This is a process where a network-wide policy is set in place to automatically disable admin accounts at the Active Directory (AD) level when the account is not in direct need. Individual users may submit their requests through an automated process that grants them access to a specified system for a set timeframe when they need to support the completion of a certain task.

In addition, CISA, FBI, MS-ISAC, and CCCS recommend network defenders apply the following mitigations to limit potential adversarial use of common system and network discovery techniques and to reduce the impact and risk of compromise by ransomware or data extortion actors:

• Disable File and Printer sharing services. If these services are required, use strong passwords or Active Directory authentication.
• Implement a recovery plan to maintain and retain multiple copies of sensitive or proprietary data and servers in a physically separate, segmented, and secure location (e.g., hard drive, storage device, or the cloud).
• Maintain offline backups of data and regularly maintain backup and restoration (daily or weekly at minimum). By instituting this practice, an organization minimizes the impact of disruption to business practices as they can retrieve their data [CPG 2.R].
• Require all accounts with password logins (e.g., service account, admin accounts, and domain admin accounts)to comply with National Institute for Standards and Technology (NIST) standards for developing and managing password policies.
  • Use longer passwords consisting of at least 15 characters [CPG 2.B].
  • Store passwords in hashed format using industry-recognized password managers.
  • Add password user “salts” to shared login credentials.
  • Avoid reusing passwords [CPG 2.C].
  • Implement multiple failed login attempt account lockouts [CPG 2.G].
  • Disable password “hints.”
  • Refrain from requiring password changes more frequently than once per year.

Note: NIST guidance suggests favoring longer passwords instead of requiring regular and frequent password resets. Frequent password resets are more likely to result in users developing password “patterns” cyber criminals can easily decipher.
* Require administrator credentials to install software.

• Require phishing-resistant multifactor authentication for all services to the extent possible, particularly for webmail, virtual private networks, and accounts that access critical systems [CPG 2.H].
• Keep all operating systems, software, and firmware up to date. Timely patching is one of the most efficient and cost-effective steps an organization can take to minimize its exposure to cybersecurity threats. Organizations should patch vulnerable software and hardware systems within 24 to 48 hours of vulnerability disclosure. Prioritize patching known exploited vulnerabilities in internet-facing systems [CPG 1.E].
• Segment networks to prevent the spread of ransomware. Network segmentation can help prevent the spread of ransomware by controlling traffic flows between—and access to various subnetworks, restricting further lateral movement [CPG 2.F].
• Identify, detect, and investigate abnormal activity and potential traversal of the indicated ransomware with a networking monitoring tool. To aid in detecting ransomware, implement a tool that logs and reports all network traffic, including lateral movement activity on a network. Endpoint detection and response (EDR) tools are particularly useful for detecting lateral connections, as they have insight into common and uncommon network connections for each host [CPG 3.A].
• Install, regularly update, and enable real time detection for antivirus software on all hosts.
• Disable unused ports [CPG 2.V].
• Consider adding an email banner to emails received from outside your organization [CPG 2.M].
• Ensure all backup data is encrypted, immutable (i.e., cannot be altered or deleted), and covers the entire organization’s data infrastructure [CPG 2.K, 2.L, 2.R].

VALIDATE SECURITY CONTROLS

In addition to applying mitigations, CISA recommends exercising, testing, and validating your organization’s security program against the threat behaviors mapped to the MITRE ATT&CK for Enterprise framework in this advisory. CISA recommends testing your existing security controls inventory to assess how they perform against the ATT&CK techniques described in this advisory.

To get started:

1. Select an ATT&CK technique described in this advisory (see Tables 5-13).
2. Align your security technologies against the technique.
3. Test your technologies against the technique.
4. Analyze your detection and prevention technologies’ performance.
5. Repeat the process for all security technologies to obtain a set of comprehensive performance data.
6. Tune your security program, including people, processes, and technologies, based on the data generated by this process.

CISA recommends continually testing your security program, at scale, in a production environment to ensure optimal performance against the MITRE ATT&CK techniques identified in this advisory.

RESOURCES

• NIST: NVD - CVE-2022-31199
• Stopransomware.gov (A whole-of-government approach with one central location for U.S. ransomware resources and alerts.)
• #StopRansomware Guide
• CISA: Implement Phishing-Resistant MFA
• CISA: Guide to Securing Remote Access Software
• CISA and MS-ISAC: Joint Ransomware Guide
• CISA: Cross-Sector Cybersecurity Performance Goals
• CL0P Ransomware Uses Truebot Malware for Access to Networks
• Field Offices – FBI
• NSA – Zero Trust Security Model

REFERENCES

[1] Bishop Fox: Netwrix Auditor Advisory

[2] Talos Intelligence: Breaking the Silence - Recent Truebot Activity

[3] The DFIR Report: Truebot Deploys Cobalt Strike and FlawedGrace

[4] MAR-10445155-1.v1 .CLEAR Truebot Activity Infects U.S. and Canada Based Networks

[5] Red Canary: Raspberry Robin Delivery Vector

[6] Microsoft: Raspberry Robin Worm Part of a Larger Ecosystem Pre-Ransomware Activity

[7] Telsy: FlawedGrace RAT

[8] VMware Security Blog: Carbon Black’s Truebot Detection

[9] GitHub: DFIR Report - Truebot Malware YARA Rule

Additional Sources

Alarming Surge in TrueBot Activity Revealed with New Delivery Vectors (thehackernews.com)

Truebot Analysis Part 1

Truebot Analysis Part 2

Truebot Analysis Part 3

Truebot Exploits Netwrix Vulnerability

TrueBot malware delivery evolves, now infects businesses in the US and elsewhere

Malpedia-Silence Downloader

Printer spooling: what is it and how to fix it? | PaperCut

ACKNOWLEDGEMENTS

VMware Carbon Black and Mandiant contributed to this CSA.

DISCLAIMER

The information in this report is being provided “as is” for informational purposes only. CISA and authoring agencies do not endorse any commercial product or service, including any subjects of analysis. Any reference to specific commercial products, processes, or services by service mark, trademark, manufacturer, or otherwise, does not constitute or imply endorsement, recommendation, or favoring by CISA, and co-sealers.