August 28, 2007
Microsoft MSN Messenger is prone to a buffer-overflow vulnerability because it fails to perform adequate boundary checks on user-supplied data. Successfully exploiting this issue allows remote attackers to execute arbitrary code in the context of the application. Failed exploit attempts will likely result in denial-of-service conditions.
- Microsoft MSN Messenger Service 6.2
- Microsoft MSN Messenger Service 7.0
- Microsoft MSN Messenger Service 7.0 beta
- Microsoft MSN Messenger Service 7.5
- Microsoft Windows Live Messenger 8.0
Run all software as a nonprivileged user with minimal access rights.
To reduce the impact of latent vulnerabilities, always run nonadministrative software as an unprivileged user with minimal access rights.
Deploy network intrusion detection systems to monitor network traffic for malicious activity.
Deploy NIDS to monitor network traffic for signs of anomalous or suspicious activity. This includes but is not limited to requests that include NOP sleds and unexplained incoming and outgoing traffic. This may indicate exploit attempts or activity that results from successful exploits.
Do not accept or execute files from untrusted or unknown sources.
To reduce the likelihood of successful exploits, never handle files that originate from unfamiliar or untrusted sources.
Do not follow links provided by unknown or untrusted sources.
To reduce the likelihood of successful attacks, never follow links provided by unknown or untrusted individuals.
Implement multiple redundant layers of security.
Various memory-protection schemes (such as nonexecutable and randomly mapped memory segments) may hinder an attacker's ability to exploit this vulnerability to execute arbitrary code.
Review and adjust according to policy any default configuration settings.
To mitigate the possibility of an exploit through HTML email, configure email clients to render messages in plain text. This mitigation may adversely affect some functionality of email clients.
The vendor has released advisory MS07-054 to address this issue. Users are advised to use the upgrade feature of the affected software to upgrade to the latest release. Please see the vendor advisory for more information.
wushi of Team509 is credited with the discovery of this vulnerability.
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