J-Security Center

Title: PuTTY Puttygen Insecure Private Key File Permissions Vulnerability

Severity: MODERATE

Description:

PuTTY is an xterm terminal and SSH implementation for Windows and UNIX systems.

PuTTY is prone to an insecure-file-permission vulnerability because of a design flaw in the affected application. Specifically, the 'puttygen' application creates private SSH key files using the standard umask. This results in 'puttygen'-derived SSH private keys being world-readable upon creation. This differs from other SSH implementation's default file permissions for private keys and is considered insecure.

An attacker could exploit this issue to access SSH private key files. This would compromise the confidentiality and integrity of a user's private SSH keys.

Version 0.58-5 on Debian Linux is affected.

NOTE: Although this vulnerability is reported to affect Debian systems at this stage, other Linux distributions may also be affected.

Affected Products:

  • Debian PuTTY 0.58.5

References:

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