Protect yourself against future threats.
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AUSCERT External Security Bulletin Redistribution
ESB-2001.222 -- OpenBSD Security Advisory
sendmail patches available
31 May 2001
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AusCERT Security Bulletin Summary
---------------------------------
Product: sendmail
Vendor: Sendmail
Operating System: OpenBSD
BSD
Linux
Unix
Impact: Denial of Service
Access Required: Local
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The signal handlers in sendmail(8) contain code that is unsafe in
the context of a signal handler. This leads to potentially serious
race conditions. At the moment this is a theoretical attack only
and can only be exploited on the local host (if at all).
According to the Sendmail, Inc. release announcement:
8.11.4 revamps signal handling within the MTA in order to reduce
the likelihood of a race condition that can lead to heap
corruption as described in Michal Zalewski's advisory. The
problems discussed in the advisory are not currently known to
be exploitable but we recommend upgrading to 8.11.4 in case a
method is found to exploit the signal handling race condition.
8.11.4 also fixes other bugs found since the release of 8.11.3.
The paper that prompted this is:
http://razor.bindview.com/publish/papers/signals.txt
Patches are available for OpenBSD 2.8:
ftp://ftp.openbsd.org/pub/OpenBSD/patches/2.8/common/028_sendmail.patch
and 2.9:
ftp://ftp.openbsd.org/pub/OpenBSD/patches/2.9/common/001_sendmail.patch
The patches referenced to above update sendmail to the 8.11.4
release. Because of this, the patch for 2.8 is rather large.
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