Description
SSH 1.2.25, 1.2.23, and other versions, when used in in CBC (Cipher Block Chaining) or CFB (Cipher Feedback 64 bits) modes, allows remote attackers to insert arbitrary data into an existing stream between an SSH client and server by using a known plaintext attack and computing a valid CRC-32 checksum for the packet, aka the "SSH insertion attack."
Advisories 1
- ICSA-21-075-02 GE UR Family (Update A) CISA ICS & IT advisories · Apr 16, 2026
References
- 19980703 UPDATE: SSH insertion attack mailing-list
- ssh-insert(1126) vdb-entry
- VU#13877 third-party-advisory
- 19980612 CORE-SDI-04: SSH insertion attack mailing-list