Date: Tue, 30 May 2000 14:46:08 -0700 (PDT)
From: Katherine M. Moussouris k8e@turbolinux.com
To: tl-security-announce@turbolinux.com
Subject: [TL-Security-Announce] xlockmore TLSA2000012-1.txt
TurboLinux Security Announcement
Package: xlockmore-4.16 and earlier
Date: Mon May 29 20:29:06 PDT 2000
Affected TurboLinux versions: 6.0.4 and earlier; 6.0.5 NOT affected
Vulnerability Type: local users can view shadowed password file
TurboLinux Advisory ID#: TLSA2000012-1
Credits: This vulnerability was discovered by COVERT labs at
Network Associates, Inc., published to BUGTRAQ Mon, 29 May 2000.
A security hole was discovered in the package mentioned above.
Please update the package in your installation as soon as possible
or disable the service.
1. Problem Summary
From the COVERT labs NAI advisory:
“The xlock program locks an X server until a valid password is
entered. The command line option -mode provides a user with a
mechanism to change the default display shown when the X server is
locked. xlock is installed with privileges to obtain password
information, although these are dropped as early as possible. An
overflow in the -mode command line option allows a malicious
attacker to reveal arbitrary portions of xlock’s address space
including the shadow password file.”
2. Impact
A local user can use the overflow to read the shadowed password
file.
3. Solution
Update the package from our ftp server by running the following
command:
rpm -Fvh ftp_path_to_filename
Where ftp_path_to_filename is the following:
ftp://ftp.turbolinux.com/pub/updates/6.0/security/xlockmore-4.16.1-1.i386.rpm
The source RPM can be downloaded here:
ftp://ftp.turbolinux.com/pub/updates/6.0/SRPMS/xlockmore-4.16.1-1.src.rpm
**Note: You must rebuild and install the RPM if you choose to
download and install the SRPM. Simply installing the SRPM alone
WILL NOT CLOSE THE SECURITY HOLE.
Please verify the MD5 checksum of the update before you
install:
MD5 sum Package Name
4987a64d63c0e803e61df11c106d33a3 xlockmore-4.16.1-1.i386.rpm fc29032bbef8b9d111b9cadd43954ecc xlockmore-4.16.1-1.src.rpm
These packages are GPG signed by Turbolinux for security. Our
key is available here:
http://www.turbolinux.com/security/tlgpgkey.asc
To verify a package, use the following command:
rpm –checksig name_of_rpm
To examine only the md5sum, use the following command:
rpm –checksig –nogpg name_of_rpm
**Note: Checking GPG keys requires RPM 3.0 or higher.
You can find more updates on our ftp server:
ftp://ftp.turbolinux.com/pub/updates/6.0/security/
for TL6.0 Workstation and Server security updates
ftp://ftp.turbolinux.com/pub/updates/4.0/security/
for TL4.0 Workstation and Server security updates
Our webpage for security announcements:
http://www.turbolinux.com/security
If you want to report vulnerabilities, please contact:
rt-security@turbolinux.com
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