Signature Detail

GOPHER: Internet Explorer Gopher Client Buffer Overflow

This signature detects attempts to exploit a known vulnerability against Microsoft Internet Explorer using the Gopher protocol. A malicious URL can be embedded in an image tag (<IMG>) on a malicious Web server to cause a client to visit that URL and become vulnerable to arbitrary code execution. If the malicious Gopher server is running on a computer other than the Web server that contained the embedded URL, attackers can send a popular bindshell() type Windows shellcode to the client after the +ABSTRACT Gopher tag.

Extended Description

Microsoft Internet Explorer, Proxy Server and ISA Server includes a gopher client. Reportedly, these clients are vulnerable to a buffer overflow condition. The vulnerability exists in the component that parses gopher replies. A malicious server is able to send a reply that will overflow the buffer and run arbitrary code on a user's system.

Affected Products

• Microsoft Internet Explorer 5.0.1
• Microsoft Internet Explorer 5.0.1 SP1
• Microsoft Internet Explorer 5.0.1 SP2
• Microsoft Internet Explorer 5.5
• Microsoft Internet Explorer 5.5 SP1
• Microsoft Internet Explorer 5.5 SP2
• Microsoft Internet Explorer 6.0
• Microsoft ISA Server 2000 SP1
• Microsoft ISA Server 2000
• Microsoft Proxy Server 2.0
• Microsoft Proxy Server 2.0 SP1

References

• BugTraq: 4930
• CVE: CVE-2002-0371
• URL: http://www.microsoft.com/technet/security/bulletin/ms02-027.asp
• URL: http://www.kb.cert.org/vuls/id/440275