Red Hat Bugzilla – Bug 232241
CVE-2007-0720 Incomplete SSL negotiation prevents other clients from connecting to CUPS server
Last modified: 2007-11-30 17:07:42 EST
Description of problem:
CUPS doesn't use separate workers for connections. During SSL
negotiation it does not accept new connections from anyone so
any user can DoS the server with unfinished negotiation.
Version-Release number of selected component (if applicable):
Both 1.2 <= 1.2.7 and 1.1 are affected.
I was able to reproduce on RHEL4, RHEL5.
FC6 (1.2.7) is already fixed.
SSL support needs to be enabled. Default in 1.2.
Steps to Reproduce:
1. Launch the attached reproducer (eventually modify appropriately)
2. Let it run for at least 10 secs (to ensure that the server is not patched)
3. Attempt another connection to the CUPS server.
The relevant fix:
http://www.cups.org/articles.php?L429+I10+T+P1+Q (r6110, r6081, r6079)
*** Bug 232242 has been marked as a duplicate of this bug. ***
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.
Comment on attachment 151009 [details]
CVE-2007-0720 reproducer that uses dribbling to DoS even a patched version
CUPS server should _NOT_ be made publically accessible from untrusted networks.
Due to the design of the server it is still vulnerable to dribbling attacks as
demonstrated by the attached reproducer. This should not be a problem at all,
there is no practical need to override local-only default and enable access to
the print server from the Internet.