Insecure DLL loading in SIMATIC STEP 7 and PCS 7

1) DDL hijacking

EUVDB-ID: #VU6192

Risk: Critical

CVSSv3.1: 9.2 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H/E:H/RL:O/RC:C]

CVE-ID: CVE-2012-3015

CWE-ID: CWE-426 - Untrusted Search Path

Exploit availability: No

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to insecure DDL loading mechanism when processing STEP 7 files in SIMATIC STEP 7 and SIMATIC PCS 7 software. A remote attacker can trick the victim into opening a SETP 7 file from a remote SMB or WebDAV share, which hosts malicious .dll file, and execute arbitrary code on the target system.

Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.

Note: the vulnerability has been exploited in the wild by Stuxnet malware in 2010.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

SIMATIC STEP 7: 5.5

SIMATIC PCS 7: 7.1 - 7.1 SP3

External links

http://www.siemens.com/cert/pool/cert/siemens_security_advisory_ssa-110665.pdf
http://ics-cert.us-cert.gov/advisories/ICSA-12-205-02

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.