Sielco Sistemi Winlog Buffer Overflow (Update A)
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ICS-CERT originally released Advisory ICSA-11-298-01P on the US-CERT secure portal on October 25, 2011. This web page release was delayed to allow users time to download and install the update.
Independent researcher Paul Davis has identified a buffer overflow vulnerability in Sielco Sistemi Winlog application. Sielco Sistemi has produced a new release that mitigates this vulnerability. Mr. Davis has indicated to ICS-CERT that he has tested the new release and validated that it resolves the vulnerability.
The following Sielco Sistemi products are affected:
- Winlog Lite versions older than Version 2.07.09
- Winlog PRO versions older than Version 2.07.09.
Successful exploitation of this vulnerability could lead to a program crash or arbitrary code execution.
Impact to individual organizations depends on many factors that are unique to each organization. ICS-CERT recommends that organizations evaluate the impact of this vulnerability based on their environment, architecture, and product implementation.
Sielco Sistemi is an Italy-based company that creates supervisory control and data acquisition (SCADA)/human-machine interface (HMI) software and hardware products.
Winlog Lite is a demo version of the Winlog PRO SCADA/HMI system. According to Sielco Sistemi, Winlog PRO is deployed across several sectors including manufacturing, public utilities, telecommunications, and others. Sielco Sistemi products are deployed in about 16 countries around the world.
In the affected versions, Winlog does not properly sanitize the inputs from project files. Invalid information in certain fields can overwrite memory locations, which causes the program to crash and could be used to execute arbitrary code.
CVE-2011-4037a has been assigned to this vulnerability.
This vulnerability is not remotely exploitable and cannot be exploited without user interaction. The exploit is only triggered when a local user runs the vulnerable application and loads the malformed file.
Existence of Exploit
No known public exploits specifically target this vulnerability.
Crafting a working exploit for this vulnerability would be difficult. Social engineering is required to convince the user to accept the malformed file. Additional user interaction is needed to load the malformed file, decreasing the likelihood of a successful exploit.
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Sielco Sistemi advises users to download the new Winlog release, from their website www.sielcosistemi.com and follow download instructions found there.
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Sielco Sistemi plans to send a message to all customers telling of the vulnerability and the new release that mitigates it. The new release can be installed in the same manner as the previous release.
ICS-CERT encourages asset owners to take the following additional defensive measures to protect against this and other cybersecurity risks:
- Minimize network exposure for all control system devices. Critical devices should not directly face the Internet.
- Locate control system networks and remote devices behind firewalls, and isolate them from the business network.
- When remote access is required, use secure methods, such as Virtual Private Networks (VPNs), recognizing that VPN is only as secure as the connected devices.
The Control Systems Security Program (CSSP) also provides a section for control system security recommended practices on the CSSP web page. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.
Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to ICS-CERT for tracking and correlation against other incidents. ICS-CERT reminds organizations to perform proper impact analysis and risk assessment prior to taking defensive measures.
In addition, ICS-CERT recommends that users take the following measures to protect themselves from social engineering attacks.
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