SeverityCVE CodeAffected ComponentSources
HighCVE-2024-31497Every version of the PuTTY tools from 0.68 to 0.80 (Os: Windows)chiark.greenend.org.uk

Summary

The Telnet/ssh client PuTTY versions 0.68 to 0.80, released before update 0.81, allows an attacker to recover the user’s private key!

This vulnerability is dangerous in scenarios where an attacker can read messages signed with PuTTY or Pageant, as a set of signed messages can be publicly available, for example, if they are stored on a public Git service that uses SSH to sign commits.

This means that an attacker may already have enough information to compromise a victim’s private key, even if vulnerable versions of PuTTY are no longer in use.

The vulnerability lies in the fact that after compromising the key, an attacker can carry out attacks on the software supply chain stored in Git.

Moreover, there is a second, independent scenario involving an attacker controlling an SSH server to which the victim is authenticating, even if that server is not fully trusted by the victim.

The operator of such a server can derive the victim’s private key and use it for unauthorized access to other services, including Git services, allowing the attacker to carry out supply chain attacks.

  • The vulnerability affects not only PuTTY but also other popular tools such as FileZilla before version 3.67.0, WinSCP before version 6.3.3, TortoiseGit before version 2.15.0.1, and TortoiseSVN before version 1.14.6.

Mitigation

  • This vulnerability has been fixed in PuTTY 0.81

  • Users of TortoiseSVN are advised to configure TortoiseSVN to use Plink from the latest PuTTY 0.81 release when accessing a SVN repository via SSH until a patch becomes available.

Read more about the technical details here