PuTTY: Remote code execution — GLSA 200502-28

PuTTY was found to contain vulnerabilities that can allow a malicious SFTP server to execute arbitrary code on unsuspecting PSCP and PSFTP clients.

Affected packages

Package 	net-misc/putty on all architectures
Affected versions 	< 0.57
Unaffected versions 	>= 0.57

Background

PuTTY is a popular SSH client, PSCP is a secure copy implementation, and PSFTP is a SSH File Transfer Protocol client.

Description

Two vulnerabilities have been discovered in the PSCP and PSFTP clients, which can be triggered by the SFTP server itself. These issues are caused by the improper handling of the FXP_READDIR response, along with other string fields.

Impact

An attacker can setup a malicious SFTP server that would send these malformed responses to a client, potentially allowing the execution of arbitrary code on their system.

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-0.57"

References

    PuTTY vulnerability vuln-sftp-readdir
    PuTTY vulnerability vuln-sftp-string
    CAN-2005-0467
    iDEFENSE Advisory