10 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
10 High
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:N/AC:L/Au:N/C:C/I:C/A:C
0.976 High
EPSS
Percentile
100.0%
This joint cybersecurity advisory uses the MITRE Adversarial Tactics, Techniques, and Common Knowledge (ATT&CK®) framework. See the ATT&CK for Enterprise framework for all referenced threat actor techniques.
Note: the analysis in this joint cybersecurity advisory is ongoing, and the information provided should not be considered comprehensive. The Cybersecurity and Infrastructure Security Agency (CISA) will update this advisory as new information is available.
This joint cybersecurity advisory was written by CISA with contributions from the Federal Bureau of Investigation (FBI).
CISA has recently observed advanced persistent threat (APT) actors exploiting multiple legacy vulnerabilities in combination with a newer privilege escalation vulnerability—CVE-2020-1472—in Windows Netlogon. The commonly used tactic, known as vulnerability chaining, exploits multiple vulnerabilities in the course of a single intrusion to compromise a network or application.
This recent malicious activity has often, but not exclusively, been directed at federal and state, local, tribal, and territorial (SLTT) government networks. Although it does not appear these targets are being selected because of their proximity to elections information, there may be some risk to elections information housed on government networks.
CISA is aware of some instances where this activity resulted in unauthorized access to elections support systems; however, CISA has no evidence to date that integrity of elections data has been compromised. There are steps that election officials, their supporting SLTT IT staff, and vendors can take to help defend against this malicious cyber activity.
Some common tactics, techniques, and procedures (TTPs) used by APT actors include leveraging legacy network access and virtual private network (VPN) vulnerabilities in association with the recent critical CVE-2020-1472 Netlogon vulnerability. CISA is aware of multiple cases where the Fortinet FortiOS Secure Socket Layer (SSL) VPN vulnerability CVE-2018-13379 has been exploited to gain access to networks. To a lesser extent, CISA has also observed threat actors exploiting the MobileIron vulnerability CVE-2020-15505. While these exploits have been observed recently, this activity is ongoing and still unfolding.
After gaining initial access, the actors exploit CVE-2020-1472 to compromise all Active Directory (AD) identity services. Actors have then been observed using legitimate remote access tools, such as VPN and Remote Desktop Protocol (RDP), to access the environment with the compromised credentials. Observed activity targets multiple sectors and is not limited to SLTT entities.
CISA recommends network staff and administrators review internet-facing infrastructure for these and similar vulnerabilities that have or could be exploited to a similar effect, including Juniper CVE-2020-1631, Pulse Secure CVE-2019-11510, Citrix NetScaler CVE-2019-19781, and Palo Alto Networks CVE-2020-2021 (this list is not considered exhaustive).
Click here for a PDF version of this report.
APT threat actors are actively leveraging legacy vulnerabilities in internet-facing infrastructure (Exploit Public-Facing Application [T1190], External Remote Services [T1133]) to gain initial access into systems. The APT actors appear to have predominately gained initial access via the Fortinet FortiOS VPN vulnerability CVE-2018-13379.
Although not observed in this campaign, other vulnerabilities, listed below, could be used to gain network access (as analysis is evolving, these listed vulnerabilities should not be considered comprehensive). As a best practice, it is critical to patch all known vulnerabilities within internet-facing infrastructure.
CVE-2018-13379 is a path traversal vulnerability in the FortiOS SSL VPN web portal. An unauthenticated attacker could exploit this vulnerability to download FortiOS system files through specially crafted HTTP resource requests.[1]
CVE-2020-15505 is a remote code execution vulnerability in MobileIron Core & Connector versions 10.3 and earlier.[2] This vulnerability allows an external attacker, with no privileges, to execute code of their choice on the vulnerable system. As mobile device management (MDM) systems are critical to configuration management for external devices, they are usually highly permissioned and make a valuable target for threat actors.
Post initial access, the APT actors use multiple techniques to expand access to the environment. The actors are leveraging CVE-2020-1472 in Windows Netlogon to escalate privileges and obtain access to Windows AD servers. Actors are also leveraging the opensource tools such as Mimikatz and the CrackMapExec tool to obtain valid account credentials from AD servers (Valid Accounts [T1078]).
CVE-2020-1472 is a vulnerability in Microsoft Windows Netlogon Remote Protocol (MS-NRPC), a core authentication component of Active Directory.[3] This vulnerability could allow an unauthenticated attacker with network access to a domain controller to completely compromise all AD identity services (Valid Accounts: Domain Accounts [T1078.002]). Malicious actors can leverage this vulnerability to compromise other devices on the network (Lateral Movement [TA0008]).
Once system access has been achieved, the APT actors use abuse of legitimate credentials (_Valid Accounts _[T1078]) to log in via VPN or remote access services (External Remote Services [T1133]) to maintain persistence.
Organizations with externally facing infrastructure devices that have the vulnerabilities listed in this joint cybersecurity advisory, or other vulnerabilities, should move forward with an “assume breach” mentality. As initial exploitation and escalation may be the only observable exploitation activity, most mitigations will need to focus on more traditional network hygiene and user management activities.
Patch systems and equipment promptly and diligently. Establishing and consistently maintaining a thorough patching cycle continues to be the best defense against adversary TTPs. See table 1 for patch information on CVEs mentioned in this report.
Table 1: Patch information for CVEs
Vulnerability | Vulnerable Products | Patch Information |
---|---|---|
CVE-2018-13379 |
FortiOS 6.0: 6.0.0 to 6.0.4
FortiOS 5.6: 5.6.3 to 5.6.7
FortiOS 5.4: 5.4.6 to 5.4.12
|
Citrix Application Delivery Controller
Citrix Gateway
Citrix SDWAN WANOP
|
Citrix blog post: firmware updates for Citrix ADC and Citrix Gateway versions 11.1 and 12.0
Citrix blog post: security updates for Citrix SD-WAN WANOP release 10.2.6 and 11.0.3
Citrix blog post: firmware updates for Citrix ADC and Citrix Gateway versions 12.1 and 13.0
Citrix blog post: firmware updates for Citrix ADC and Citrix Gateway version 10.5
CVE-2020-5902 |
Big-IP devices (LTM, AAM, Advanced WAF, AFM, Analytics, APM, ASM, DDHD, DNS, FPS, GTM, Link Controller, PEM, SSLO, CGNAT)
|
F5 Security Advisory: K52145254: TMUI RCE vulnerability CVE-2020-5902
CVE-2019-11510 |
Pulse Connect Secure 9.0R1 - 9.0R3.3, 8.3R1 - 8.3R7, 8.2R1 - 8.2R12, 8.1R1 - 8.1R15
Pulse Policy Secure 9.0R1 - 9.0R3.1, 5.4R1 - 5.4R7, 5.3R1 - 5.3R12, 5.2R1 - 5.2R12, 5.1R1 - 5.1R15
|
Pulse Secure Out-of-Cycle Advisory: Multiple vulnerabilities resolved in Pulse Connect Secure / Pulse Policy Secure 9.0RX
CVE-2020-15505 |
MobileIron Core & Connector versions 10.3.0.3 and earlier, 10.4.0.0, 10.4.0.1, 10.4.0.2, 10.4.0.3, 10.5.1.0, 10.5.2.0 and 10.6.0.0
Sentry versions 9.7.2 and earlier, and 9.8.0;
Monitor and Reporting Database (RDB) version 2.0.0.1 and earlier
|
MobileIron Blog: MobileIron Security Updates Available
CVE-2020-1631 |
Junos OS 12.3, 12.3X48, 14.1X53, 15.1, 15.1X49, 15.1X53, 17.2, 17.3, 17.4, 18.1, 18.2, 18.3, 18.4, 19.1, 19.2, 19.3, 19.4, 20.1
|
PAN-OS 9.1 versions earlier than PAN-OS 9.1.3; PAN-OS 9.0 versions earlier than PAN-OS 9.0.9; PAN-OS 8.1 versions earlier than PAN-OS 8.1.15, and all versions of PAN-OS 8.0 (EOL)
|
Palo Alto Networks Security Advisory for CVE-2020-2021
CVE-2020-1472 |
Windows Server 2008 R2 for x64-based Systems Service Pack 1
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
Windows Server 2012
Windows Server 2012 (Server Core installation)
Windows Server 2012 R2
Windows Server 2016
Windows Server 2019
Windows Server 2019 (Server Core installation)
Windows Server, version 1903 (Server Core installation)
Windows Server, version 1909 (Server Core installation)
Windows Server, version 2004 (Server Core installation)
|
If there is an observation of CVE-2020-1472 Netlogon activity or other indications of valid credential abuse detected, it should be assumed the APT actors have compromised AD administrative accounts, the AD forest should not be fully trusted, and, therefore, a new forest should be deployed. Existing hosts from the old compromised forest cannot be migrated in without being rebuilt and rejoined to the new domain, but migration may be done through “creative destruction,” wherein as endpoints in the legacy forest are decommissioned, new ones can be built in the new forest. This will need to be completed on on-premise as well as Azure-hosted AD instances.
Note that fully resetting an AD forest is difficult and complex; it is best done with the assistance of personnel who have successfully completed the task previously.
It is critical to perform a full password reset on all user and computer accounts in the AD forest. Use the following steps as a guide.
krbtgt
) password [4]; this must be completed before any additional actions (a second reset will take place in step 5)1. User accounts (forced reset with no legacy password reuse)
2. Local accounts on hosts (including local accounts not covered by Local Administrator Password Solution [LAPS])
3. Service accounts
4. Directory Services Restore Mode (DSRM) account
5. Domain Controller machine account
6. Application passwords
krbtgt
password againkrbtgt
reset to propagate to all domain controllers (time may vary)The following accounts should be reset:
To secure your organization’s Netlogon channel connections:
To protect your organization against this CVE, follow advice from Microsoft, including:
Implement the following recommendations to secure your organization’s VPNs:
Discontinue unused VPN servers. Reduce your organization’s attack surface by discontinuing unused VPN servers, which may act as a point of entry for attackers. To protect your organization against VPN vulnerabilities:
Recipients of this report are encouraged to contribute any additional information that they may have related to this threat.
For any questions related to this report or to report an intrusion and request resources for incident response or technical assistance, please contact:
DISCLAIMER
This information is provided “as is” for informational purposes only. The United States Government does not provide any warranties of any kind regarding this information. In no event shall the United States Government or its contractors or subcontractors be liable for any damages, including but not limited to, direct, indirect, special or consequential damages, arising out of, resulting from, or in any way connected with this information, whether or not based upon warranty, contract, tort, or otherwise, whether or not arising out of negligence, and whether or not injury was sustained from, or arose out of the results of, or reliance upon the information.
The United States Government does 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 their endorsement, recommendation, or favoring by the United States Government.
[1] Fortinet Advisory: FG-IR-18-384
[2] MobileIron Blog: MobileIron Security Updates Available
[3] Microsoft Security Advisory for CVE-2020-1472
[4] Microsoft: AD Forest Recovery - Resetting the krbtgt password
October 9, 2020: Initial Version|October 11, 2020: Updated Summary|October 12, 2020: Added Additional Links
attack.mitre.org/versions/v7/matrices/enterprise/
attack.mitre.org/versions/v7/tactics/TA0008/
attack.mitre.org/versions/v7/techniques/T1078/
attack.mitre.org/versions/v7/techniques/T1078/
attack.mitre.org/versions/v7/techniques/T1078/002/
attack.mitre.org/versions/v7/techniques/T1133/
attack.mitre.org/versions/v7/techniques/T1133/
attack.mitre.org/versions/v7/techniques/T1190/
docs.microsoft.com/en-us/windows-server/identity/ad-ds/manage/ad-forest-recovery-resetting-the-krbtgt-password
docs.microsoft.com/en-us/windows-server/identity/ad-ds/manage/ad-forest-recovery-resetting-the-krbtgt-password
kb.juniper.net/InfoCenter/index?page=content&id=JSA11021
kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44101
learn.cisecurity.org/ms-isac-subscription
media.defense.gov/2020/Jul/02/2002355501/-1/-1/0/CONFIGURING_IPSEC_VIRTUAL_PRIVATE_NETWORKS_2020_07_01_FINAL_RELEASE.PDF
nvd.nist.gov/vuln/detail/CVE-2018-13379
nvd.nist.gov/vuln/detail/CVE-2018-13379
nvd.nist.gov/vuln/detail/CVE-2018-13379
nvd.nist.gov/vuln/detail/CVE-2018-13379
nvd.nist.gov/vuln/detail/CVE-2019-11510
nvd.nist.gov/vuln/detail/CVE-2019-11510
nvd.nist.gov/vuln/detail/CVE-2019-11510
nvd.nist.gov/vuln/detail/CVE-2019-19781
nvd.nist.gov/vuln/detail/CVE-2019-19781
nvd.nist.gov/vuln/detail/CVE-2019-19781
nvd.nist.gov/vuln/detail/CVE-2020-1472
nvd.nist.gov/vuln/detail/CVE-2020-1472
nvd.nist.gov/vuln/detail/CVE-2020-1472
nvd.nist.gov/vuln/detail/CVE-2020-1472
nvd.nist.gov/vuln/detail/CVE-2020-15505
nvd.nist.gov/vuln/detail/CVE-2020-15505
nvd.nist.gov/vuln/detail/CVE-2020-15505
nvd.nist.gov/vuln/detail/CVE-2020-15505
nvd.nist.gov/vuln/detail/CVE-2020-1631
nvd.nist.gov/vuln/detail/CVE-2020-1631
nvd.nist.gov/vuln/detail/CVE-2020-2021
nvd.nist.gov/vuln/detail/CVE-2020-2021
nvd.nist.gov/vuln/detail/CVE-2020-2021
nvd.nist.gov/vuln/detail/CVE-2020-5902
nvd.nist.gov/vuln/detail/CVE-2020-5902
portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1472
portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1472
portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1472
portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1472
portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1472
portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1472
portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1472
portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1472
public.govdelivery.com/accounts/USDHSCISA/subscriber/new?topic_id=USDHSCISA_138
public.govdelivery.com/accounts/USDHSUSCERT/subscriber/new
security.paloaltonetworks.com/CVE-2020-2021
support.f5.com/csp/article/K52145254
support.microsoft.com/en-us/help/4557222/how-to-manage-the-changes-in-netlogon-secure-channel-connections-assoc
twitter.com/CISAgov
twitter.com/intent/tweet?text=APT%20Actors%20Chaining%20Vulnerabilities%20Against%20SLTT%2C%20Critical%20Infrastructure%2C%20and%20Elections%20Organizations+https://www.cisa.gov/news-events/cybersecurity-advisories/aa20-283a
us-cert.cisa.gov/ncas/alerts/aa20-010a
us-cert.cisa.gov/ncas/alerts/aa20-031a
us-cert.cisa.gov/ncas/alerts/aa20-073a
us-cert.cisa.gov/ncas/alerts/aa20-245a
us-cert.cisa.gov/ncas/tips/ST04-002
us-cert.cisa.gov/ncas/tips/ST04-006
us-cert.cisa.gov/ncas/tips/ST04-006
us-cert.cisa.gov/ncas/tips/ST05-012
us-cert.cisa.gov/ncas/tips/ST18-001
www.cisa.gov/sites/default/files/publications/Risk%20and%20Vulnerability%20Assessment%20%28RVA%29%20Mapped%20to%20the%20MITRE%20ATT%26amp%3BCK%20Framework%20Infographic_v6-100620_%20508.pdf
www.cisa.gov/vpn-related-guidance
www.citrix.com/blogs/2020/01/19/vulnerability-update-first-permanent-fixes-available-timeline-accelerated/
www.citrix.com/blogs/2020/01/22/update-on-cve-2019-19781-fixes-now-available-for-citrix-sd-wan-wanop/
www.citrix.com/blogs/2020/01/23/fixes-now-available-for-citrix-adc-citrix-gateway-versions-12-1-and-13-0/
www.citrix.com/blogs/2020/01/24/citrix-releases-final-fixes-for-cve-2019-19781/
www.dhs.gov
www.dhs.gov/foia
www.dhs.gov/performance-financial-reports
www.facebook.com/CISA
www.facebook.com/sharer/sharer.php?u=https://www.cisa.gov/news-events/cybersecurity-advisories/aa20-283a&title=APT%20Actors%20Chaining%20Vulnerabilities%20Against%20SLTT%2C%20Critical%20Infrastructure%2C%20and%20Elections%20Organizations
www.fbi.gov/contact-us/field-offices/field-offices
www.fortiguard.com/psirt/FG-IR-18-384
www.fortiguard.com/psirt/FG-IR-18-384
www.fortiguard.com/psirt/FG-IR-18-384
www.instagram.com/cisagov
www.linkedin.com/company/cybersecurity-and-infrastructure-security-agency
www.linkedin.com/sharing/share-offsite/?url=https://www.cisa.gov/news-events/cybersecurity-advisories/aa20-283a
www.mobileiron.com/en/blog/mobileiron-security-updates-available
www.mobileiron.com/en/blog/mobileiron-security-updates-available
www.mobileiron.com/en/blog/mobileiron-security-updates-available
www.oig.dhs.gov/
www.surveymonkey.com/r/CISA-cyber-survey?product=https://www.cisa.gov/news-events/cybersecurity-advisories/aa20-283a
www.usa.gov/
www.whitehouse.gov/
www.youtube.com/@cisagov
mailto:?subject=APT%20Actors%20Chaining%20Vulnerabilities%20Against%20SLTT%2C%20Critical%20Infrastructure%2C%20and%20Elections%20Organizations&body=www.cisa.gov/news-events/cybersecurity-advisories/aa20-283a
10 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
10 High
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:N/AC:L/Au:N/C:C/I:C/A:C
0.976 High
EPSS
Percentile
100.0%