CVE-2022-29245

Vulnerability Description

SSH.NET is a Secure Shell (SSH) library for .NET. In versions 2020.0.0 and 2020.0.1, during an `X25519` key exchange, the client’s private key is generated with `System.Random`. `System.Random` is not a cryptographically secure random number generator, it must therefore not be used for cryptographic purposes. When establishing an SSH connection to a remote host, during the X25519 key exchange, the private key is generated with a weak random number generator whose seed can be brute forced. This allows an attacker who is able to eavesdrop on the communications to decrypt them. Version 2020.0.2 contains a patch for this issue. As a workaround, one may disable support for `curve25519-sha256` and `[email protected]` key exchange algorithms.

CVSS Score

Affected Products

Related Weaknesses (CWE)

References

• https://github.com/sshnet/SSH.NET/blob/bc99ada7da3f05f50d9379f2644941d91d5bf05a/ExploitThird Party Advisory
• https://github.com/sshnet/SSH.NET/commit/03c6d60736b8f7b42e44d6989a53f9b644a091fPatchThird Party Advisory
• https://github.com/sshnet/SSH.NET/releases/tag/2020.0.2Release NotesThird Party Advisory
• https://github.com/sshnet/SSH.NET/security/advisories/GHSA-72p8-v4hg-v45pExploitMitigationThird Party Advisory
• https://github.com/sshnet/SSH.NET/blob/bc99ada7da3f05f50d9379f2644941d91d5bf05a/ExploitThird Party Advisory
• https://github.com/sshnet/SSH.NET/commit/03c6d60736b8f7b42e44d6989a53f9b644a091fPatchThird Party Advisory
• https://github.com/sshnet/SSH.NET/releases/tag/2020.0.2Release NotesThird Party Advisory
• https://github.com/sshnet/SSH.NET/security/advisories/GHSA-72p8-v4hg-v45pExploitMitigationThird Party Advisory