|Reported by:||Owned by:|
Changes since OpenSSH 7.1p1 ===========================
- SECURITY: ssh(1): The OpenSSH client code between 5.4 and 7.1 contains experimental support for resuming SSH-connections (roaming).
The matching server code has never been shipped, but the client code was enabled by default and could be tricked by a malicious server into leaking client memory to the server, including private client user keys.
The authentication of the server host key prevents exploitation by a man-in-the-middle, so this information leak is restricted to connections to malicious or compromised servers.
MITIGATION: For OpenSSH >= 5.4 the vulnerable code in the client can be completely disabled by adding 'UseRoaming no' to the gobal ssh_config(5) file, or to user configuration in ~/.ssh/config, or by passing -oUseRoaming=no on the command line.
PATCH: See below for a patch to disable this feature (Disabling Roaming in the Source Code).
This problem was reported by the Qualys Security Advisory team.
- SECURITY: Fix an out of-bound read access in the packet handling code. Reported by Ben Hawkes.
- PROTOCOL: Correctly interpret the 'first_kex_follows' option during the intial key exchange. Reported by Matt Johnston.
- Further use of explicit_bzero has been added in various buffer handling code paths to guard against compilers aggressively doing dead-store removal.