CVE-1999-1085: Medium severity ssh secure shell vulnerability
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."
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
Configure SSH servers and clients to disable CBC and CFB (64-bit) cipher modes (do not allow SSH connections that negotiate CBC or CFB64 ciphers). Prefer non-CBC/CFB cipher modes where supported.
SSH (Secure Shell) ciphers = disable CBC and CFB (64-bit) modes - Compensating control
Until a patched SSH implementation is available, restrict SSH access via network controls: allow SSH only from trusted IPs, place management interfaces on isolated networks/VLANs, and enforce firewall rules or ACLs to limit exposure.
Event History
Frequently Asked Questions
What is the severity of CVE-1999-1085?
CVE-1999-1085 is considered a moderate severity vulnerability affecting SSH versions 1.2.25 and 1.2.23.
How do I fix CVE-1999-1085?
To mitigate CVE-1999-1085, upgrade to a patched version of SSH that is not vulnerable to known plaintext attacks.
What versions of SSH are affected by CVE-1999-1085?
CVE-1999-1085 affects SSH versions 1.2.25, 1.2.23, and potentially other SSH implementations in CBC or CFB mode.
Can CVE-1999-1085 be exploited remotely?
Yes, CVE-1999-1085 can be exploited remotely by an attacker who can inject arbitrary data into the SSH stream.
What types of attacks are possible with CVE-1999-1085?
CVE-1999-1085 allows for known plaintext attacks which can compromise the integrity of the data sent over SSH.