Date: Mon, 14 Jan 2002 16:49:35 -0500 (EST)
From: EnGarde Secure Linux <[email protected]>
To: [email protected], [email protected]Subject: [ESA-20020114-001] 'sudo' can invoke the system MTA as root
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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. |
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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 <filename>
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 <filename>
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 <[email protected]>
sudo's Official Web Site:
http://www.sudo.ws/sudo/
Security Contact: [email protected]
EnGarde Advisories: http://www.engardelinux.org/advisories.html
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$Id: ESA-20020114-001-sudo,v 1.1 2002/01/14 17:36:06 rwm Exp $
- --------------------------------------------------------------------------
Author: Ryan W. Maple, <[email protected]>
Copyright 2002, Guardian Digital, Inc.
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