Opened 7 years ago

Closed 7 years ago

#7361 closed enhancement (fixed)


Reported by: bdubbs@… Owned by: ken@…
Priority: high Milestone: 7.9
Component: BOOK Version: SVN
Severity: normal Keywords:


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.

Change History (2)

comment:1 by ken@…, 7 years ago

Owner: changed from blfs-book@… to ken@…
Status: newassigned

Fixes CVE-2016-{0777,8}.

comment:2 by ken@…, 7 years ago

Resolution: fixed
Status: assignedclosed

Fixed at r16811.

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