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+------------------------------------------------------------------------+ | EnGarde Secure Linux Security Advisory January 14, 2002 | | http://www.engardelinux.org/ ESA-20020114-001 | | | | Package: sudo | | Summary: sudo can invoke the system MTA as root. | +------------------------------------------------------------------------+ EnGarde Secure Linux is a secure distribution of Linux that features improved access control, host and network intrusion detection, Web based secure remote management, complete e-commerce using AllCommerce, and integrated open source security tools. OVERVIEW -------- There is a vulnerability in sudo which can allow an attacker to trick sudo into running the system MTA with root privileges and an unclean environment, possibly leading to a root compromise. DETAIL ------ Sebastian Krahmer of the SuSE Security Team found a bug in sudo which can allow an attacker to send a failed-invocation email with root privileges and an unclean environment. Using the Postfix MTA an attacker can potentially gain a root shell. No other MTA is known to be exploitable at this time. We would like to reiterate that the bug is in sudo, not Postfix which is simply being used as a vehicle in this instance. This bug is fixed by having sudo run the MTA with user privileges instead of with root privileges. SOLUTION -------- This information applies only to EnGarde Secure Linux Community edition users. Registered users of the EnGarde Secure Linux Professional edition can use the Guardian Digital Secure Network to upgrade their packages automatically. All users should upgrade to the most recent version as outlined in this advisory. All updates may be found at: ftp://ftp.engardelinux.org/pub/engarde/stable/updates/ http://ftp.engardelinux.org/pub/engarde/stable/updates/ Before upgrading the package, the machine must either: a) be booted into a "standard" kernel; or b) have LIDS disabled. To disable LIDS, execute the command: # /sbin/lidsadm -S -- -LIDS_GLOBAL To install the updated package, execute the command: # rpm -Uvh You must now update the LIDS configuration by executing the command: # /usr/sbin/config_lids.pl To re-enable LIDS (if it was disabled), execute the command: # /sbin/lidsadm -S -- +LIDS_GLOBAL To verify the signatures of the updated packages, execute the command: # rpm -Kv UPDATED PACKAGES ---------------- These updated packages are for EnGarde Secure Linux 1.0.1 (Finestra). Source Packages: SRPMS/sudo-1.6.4-1.0.6.src.rpm MD5 Sum: bf14204686a62f01b429eb28d83cfd6b Binary Packages: i386/sudo-1.6.4-1.0.6.i386.rpm MD5 Sum: 83fceade44a6d263647653351c2acade i686/sudo-1.6.4-1.0.6.i686.rpm MD5 Sum: 8b8c9344cbc950cd9fd4f2fc1c3136f8 REFERENCES ---------- Guardian Digital's public key: http://ftp.engardelinux.org/pub/engarde/ENGARDE-GPG-KEY Credit for the discovery of this bug goes to: Sebastian Krahmer <krahmer@suse.de> sudo's Official Web Site: http://www.sudo.ws/sudo/ Security Contact: security@guardiandigital.com EnGarde Advisories: http://www.engardelinux.org/advisories.html -------------------------------------------------------------------------- $Id: ESA-20020114-001-sudo,v 1.1 2002/01/14 17:36:06 rwm Exp $ -------------------------------------------------------------------------- Author: Ryan W. Maple, <ryan@guardiandigital.com> Copyright 2002, Guardian Digital, Inc.