Red Hat Bugzilla – Bug 454566
kernel: randomize udp port allocation
Last modified: 2015-09-02 13:43:36 EDT
The Linux kernel 2.6.24 implements random source ports for UDP (where none is specified by the application). However, we do not ship a kernel that implements UDP port randomization in Red Hat Enterprise Linux 2.1, 3, 4, or 5. This bug is created to make sure that we backport a kernel patch that would cause UDP port allocation to be randomized like TCP.
Proposed upstream patch: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=32c1da70810017a98aa6c431a5494a302b6b9a30
Created attachment 311337 [details] Upstream patch for this issue
Implementing this would mitigate CVE-2008-1447 as applied to the glibc stub resolver.
Created attachment 311378 [details] Proposed backported patch for RHEL-4.8
Created attachment 311379 [details] Proposed backported patch for RHEL-5.3
Created attachment 311434 [details] Proposed backported patch for RHEL-2.1
Created attachment 311435 [details] Proposed backported patch for RHEL-3.9
Whilst we're providing updates for Red Hat Enterprise Linux 4 and 5 to backport this functionality we have not labeled them as a security fix because they're only a partial help towards mitigation. The glibc stub resolver is not a recursive resolver and therefore is not affected directly by the recent DNS exploits (which rely on a caching recursive resolver). Different attacks against stub resolvers may still be possible, but for the most part an attacker would need to be on a local network and would be likely to be able to perform other attacks more easily.