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===========================================================================
             AUSCERT External Security Bulletin Redistribution

                 ESB-2001.222 -- OpenBSD Security Advisory
                        sendmail patches available
                                31 May 2001

===========================================================================

        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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