GLSA 200410-29: PuTTY: Pre-authentication buffer overflow

http://security.gentoo.org/

Severity:	normal
Title:	PuTTY: Pre-authentication buffer overflow
Date:	10/27/2004
Bugs:	#69123
ID:	200410-29

Synopsis

PuTTY contains a vulnerability allowing an SSH server to execute arbitrary code on the connecting client.

Background

PuTTY is a free implementation of Telnet and SSH for Win32 and Unix platforms, along with an xterm terminal emulator.

Affected packages

Package	Vulnerable	Unaffected	Architecture(s)
net-misc/putty	<= 0.55	>= 0.56	All supported architectures

Description

PuTTY fails to do proper bounds checking on SSH2_MSG_DEBUG packets. The "stringlen" parameter value is incorrectly checked due to signedness issues. Note that this vulnerability is similar to the one described in GLSA 200408-04 but not the same.

Impact

When PuTTY connects to a server using the SSH2 protocol, an attacker may be able to send specially crafted packets to the client, resulting in the execution of arbitrary code with the permissions of the user running PuTTY. Note that this is possible during the authentication process but before host key verification.

Workaround

There is no known workaround at this time.

Resolution

All PuTTY users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=net-misc/putty-0.56"

References

Availability

This GLSA and any updates to it are available for viewing at the Gentoo Security Website: http://security.gentoo.org/glsa/glsa-200410-29.xml

Concerns?

Security is a primary focus of Gentoo Linux and ensuring the confidentiality and security of our users machines is of utmost importance to us. Any security concerns should be addressed to security@gentoo.org or alternatively, you may file a bug at https://bugs.gentoo.org.