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 `curve25519-sha256@libssh.org` key exchange algorithms.
CVSS 3.x
| Source | Score | Severity | Vector | Exploitability | Impact |
|---|---|---|---|---|---|
| security-advisories@github.com | 6.5 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N | 2.8 | 3.6 |
| nvd@nist.gov | 5.9 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N | 2.2 | 3.6 |
CVSS 2.0
Severity: MEDIUM
Problem Type: CWE-338,
Products Affected
| Vendor | Product | Version |
|---|---|---|
| ssh.net_project | ssh.net | 2020.0.0 |
| ssh.net_project | ssh.net | 2020.0.1 |