Share your story
The central voice for Linux and Open Source security news
Home News Topics Advisories HOWTOs Features Newsletters About Register

Sign up!
EnGarde Community
What is the most important Linux security technology?
Linux Events
Linux User Groups
Link to Us
Security Center
Book Reviews
Security Dictionary
Security Tips
White Papers
Featured Blogs
All About Linux
DanWalsh LiveJournal
Latest Newsletters
Linux Advisory Watch: March 27th, 2015
Linux Security Week: March 23rd, 2015
LinuxSecurity Newsletters
Choose Lists:
About our Newsletters
RSS Feeds
Get the LinuxSecurity news you want faster with RSS
Powered By

FreeBSD: sendmail remote exploit Print E-mail
User Rating:      How can I rate this item?
Posted by Team   
FreeBSD A remote vulnerability exists that can result in commands can be executed with administrative privileges.

FreeBSD-SA-03:04.sendmail                                   Security Advisory
                                                          The FreeBSD Project

Topic:          sendmail header parsing buffer overflow

Category:       contrib
Module:         contrib_sendmail
Announced:      2003-03-03
Credits:        Mark Dowd (ISS)
Affects:        All releases prior to 4.8-RELEASE and 5.0-RELEASE-p4
                FreeBSD 4-STABLE prior to the correction date
Corrected:      2003-03-03
FreeBSD only:   NO

I.   Background

FreeBSD includes sendmail(8), a general purpose internetwork mail
routing facility, as the default Mail Transfer Agent (MTA).

II.  Problem Description

ISS has identified a buffer overflow that may occur during header
parsing in all versions of sendmail after version 5.79.

In addition, Sendmail, Inc. has identified and corrected a defect in
buffer handling within sendmail's RFC 1413 ident protocol support.

III. Impact

A remote attacker could create a specially crafted message that may
cause sendmail to execute arbitrary code with the privileges of the
user running sendmail, typically root.  The malicious message might be
handled (and therefore the vulnerability triggered) by the initial
sendmail MTA, any relaying sendmail MTA, or by the delivering sendmail
process.  Exploiting this defect is particularly difficult, but is
believed to be possible.

The defect in the ident routines is not believed to be exploitable.

IV.  Workaround

There is no workaround, other than disabling sendmail.

V.   Solution

Do one of the following:

1) Upgrade your vulnerable system to 4-STABLE; or to the RELENG_5_0,
RELENG_4_7, or RELENG_4_6 security branch dated after the correction
date (5.0-RELEASE-p4, 4.7-RELEASE-p7, or 4.6.2-RELEASE-p10,

[NOTE: At the time of this writing, the FreeBSD 4-STABLE branch is
 labeled `4.8-RC1'.]

2) To patch your present system:

The following patch has been verified to apply to FreeBSD 5.0, 4.7,
and 4.6 systems.

a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.

b) Execute the following commands as root:

# cd /usr/src
# patch < /path/to/patch
# cd /usr/src/lib/libsm
# make obj && make depend && make
# cd /usr/src/lib/libsmutil
# make obj && make depend && make
# cd /usr/src/usr.sbin/sendmail
# make obj && make depend && make && make install

3) For i386 systems only, a patched sendmail binary is available.
Select the correct binary based on your FreeBSD version and whether or
not you want STARTTLS support.  If you want STARTTLS support, you must
have the crypto distribution installed.

a) Download the relevant binary from the location below, and verify
the detached PGP signature using your PGP utility.

b) Install the binary.  Execute the following commands as root.
Note that these examples utilizes the FreeBSD 4.7 crypto binary.
Substitute BINARYGZ with the file name which you downloaded in
step (a).

# BINARYGZ=/path/to/sendmail-4.7-i386-crypto.bin.gz
# gunzip ${BINARYGZ}
# install -s -o root -g smmsp -m 2555 ${BINARYGZ%.gz} /usr/libexec/sendmail/sendmail

c) Restart sendmail.  Execute the following command as root.

# /bin/sh /etc/rc.sendmail restart

VI.  Correction details

The following list contains the revision numbers of each file that was
corrected in FreeBSD.

Path                                                             Revision
- -------------------------------------------------------------------------
- -------------------------------------------------------------------------

VII. References

< Prev   Next >


Latest Features
Peter Smith Releases Linux Network Security Online
Securing a Linux Web Server
Password guessing with Medusa 2.0
Password guessing as an attack vector
Squid and Digest Authentication
Squid and Basic Authentication
Demystifying the Chinese Hacking Industry: Earning 6 Million a Night
Free Online security course (LearnSIA) - A Call for Help
What You Need to Know About Linux Rootkits
Review: A Practical Guide to Fedora and Red Hat Enterprise Linux - Fifth Edition
Yesterday's Edition
FBI Quietly Removes Recommendation To Encrypt Your Phone
And the prize for LEAST SECURE BROWSER goes to ... Chrome!
Partner Sponsor

Community | HOWTOs | Blogs | Features | Book Reviews | Networking
 Security Projects |  Latest News |  Newsletters |  SELinux |  Privacy |  Home
 Hardening |   About Us |   Advertise |   Legal Notice |   RSS |   Guardian Digital
(c)Copyright 2015 Guardian Digital, Inc. All rights reserved.