SSH protocol 1.5 session key recovery

ssh-session-key-recovery (6082) The risk level is classified as HighHigh Risk


SSH (SecureShell) could allow an attacker to obtain the session key from an SSH session, due to a vulnerability in the key exchange. SSH protocol version 1.5 uses the PKCS#1_1.5 public key encryption to make the key exchange between the client and the server upon connection. An attacker could use David Bleichenbacher's ciphertext attack to obtain the session key from an SSH session and obtain information about the crypto operation.


Obtain Information


For SSH-1 through 1.2.31:
Upgrade to SSH2, available from the SSH Secure Shell Download Page. See References.

For Debian Linux 2.2 (potato):
Upgrade to the latest version of openssh (1.2.3-9.2 or later), as listed in DSA-027-1. See References.

For AppGate:
Apply the patch for this vulnerability, available from the AppGate Support Web or request form from See References.

For Cisco IOS 12.0 and later:
Upgrade to the latest software release, as listed in Cisco Systems Field Notice, June 27, 2001. See References.


Platforms Affected:

  • Debian Debian Linux 2.2


Feb 07, 2001

The information within this database may change without notice. Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. In no event shall the author/distributor (IBM Internet Security Systems X-Force) be held liable for any damages whatsoever arising out of or in connection with the use or spread of this information.

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