INFORMATION BULLETIN
INFORMATION BULLETIN
| PROBLEM: | A vulnerability exists in the pam_xauth module that would forward authorization information from the root account to unprivileged users. |
| PLATFORM: | Red Hat Linux 7.1 Red Hat Linux 7.2 Red Hat Linux 7.3 Red Hat Linux 8.0 |
| DAMAGE: | Upgrade of privileges resulting in potential unauthorized root access to system. |
| SOLUTION: | Apply updated packages as stated in Red Hat's advisory. |
| VULNERABILITY ASSESSMENT: |
The risk is MEDIUM. In order to exploit this vulnerability, an attacker must have a legitimate account on the system. The attacker would have to get the administrator, as root, to 'su' to the account belonging to the attacker. |
| LINKS: | |
| CIAC BULLETIN: | http://www.ciac.org/ciac/bulletins/n-045.shtml |
| ORIGINAL BULLETIN: | https://rhn.redhat.com/errata/RHSA-2003-035.html |
| ADDITIONAL INFORMATION: |
SUN LINUX 5.0 - http://sunsolve.sun.com/pub-cgi/retrieve.pl?doc=fsalert%2F55760&zone_32=category%3Asecurity |
REVISION HISTORY: 7/28/03 - Added link to Sun's Alert #55760. [***** Start Red Hat Advisory RHSA-2003: 035-10 *****] Updated PAM packages fix bug in pam_xauth module Advisory: RHSA-2003:035-10 Last updated on: 2003-02-12 Affected Products: Red Hat Linux 7.1 Red Hat Linux 7.2 Red Hat Linux 7.3 Red Hat Linux 8.0 CVEs (cve.mitre.org): CAN-2002-1160 Security Advisory Details: Updated PAM packages are now available for Red Hat Linux 7.1, 7.2, 7.3, and 8.0. These packages correct a bug in pam_xauth's handling of authorization data for the root user. The pam_xauth module is used to forward xauth information from user to user in applications such as 'su'. Andreas Beck discovered that versions of pam_xauth supplied with Red Hat Linux since version 7.1 would forward authorization information from the root account to unprivileged users. This could be used by a local attacker to gain access to an administrator's X session. In order to exploit this vulnerability, the attacker would have to get the administrator, as root, to use su to the account belonging to the attacker. Users of pam_xauth are advised to upgrade to these errata packages, which contain a patch that adds ACL (access control list) functionality to pam_xauth and disallows root forwarding by default. Versions of pam_xauth included in Red Hat Linux 7 and earlier disabled passing of credentials from the root account to unprivileged users by default and are not affected by this issue. Thanks to Andreas Beck for reporting this issue. Updated packages: Red Hat Linux 7.1 -------------------------------------------------------------------------------- SRPMS: pam-0.75-46.7.1.src.rpm [ via FTP ] [ via HTTP ] 4a869dd0efd82fb9f098cc4284263aeb i386: pam-0.75-46.7.1.i386.rpm [ via FTP ] [ via HTTP ] 2ee6c4e7c9c59efdf3e31c8d9482a30a pam-devel-0.75-46.7.1.i386.rpm [ via FTP ] [ via HTTP ] 0d8f6cb6d0f293cb174f3e376c21eb1d Red Hat Linux 7.2 -------------------------------------------------------------------------------- SRPMS: pam-0.75-46.7.2.src.rpm [ via FTP ] [ via HTTP ] fcbe7194fc12466d4532b213373c3ce6 i386: pam-0.75-46.7.2.i386.rpm [ via FTP ] [ via HTTP ] 7d16c011e4f74e8e02bb8c193506186d pam-devel-0.75-46.7.2.i386.rpm [ via FTP ] [ via HTTP ] 0919b62d8d7531883d6e01f5ff3a51b6 ia64: pam-0.75-46.7.2.ia64.rpm [ via FTP ] [ via HTTP ] e653e3ff25eb958570b411d201b5106e pam-devel-0.75-46.7.2.ia64.rpm [ via FTP ] [ via HTTP ] 8f4d0dc64cdbded20c46a38460e6affe Red Hat Linux 7.3 -------------------------------------------------------------------------------- SRPMS: pam-0.75-46.7.3.src.rpm [ via FTP ] [ via HTTP ] 99751631043fbe42f98f8598e74e6d4b i386: pam-0.75-46.7.3.i386.rpm [ via FTP ] [ via HTTP ] 8ea6d868c28c22d629d2059f1ad72f1b pam-devel-0.75-46.7.3.i386.rpm [ via FTP ] [ via HTTP ] 9fef754632838504c0590ba30203a925 Red Hat Linux 8.0 -------------------------------------------------------------------------------- SRPMS: pam-0.75-46.8.0.src.rpm [ via FTP ] [ via HTTP ] 1b74821ca4fd0b7a9919c3b0fdf3dbb3 i386: pam-0.75-46.8.0.i386.rpm [ via FTP ] [ via HTTP ] 25ebcb39f56c98cc064c34b2d048ed35 pam-devel-0.75-46.8.0.i386.rpm [ via FTP ] [ via HTTP ] f6412156d54a4021a3200eb7d7ff79c0 Solution Before applying this update, make sure all previously released errata relevant to your system have been applied. To update all RPMs for your particular architecture, run: rpm -Fvh [filenames] where [filenames] is a list of the RPMs you wish to upgrade. Only those RPMs which are currently installed will be updated. Those RPMs which are not installed but included in the list will not be updated. Note that you can also use wildcards (*.rpm) if your current directory *only* contains the desired RPMs. Please note that this update is also available via Red Hat Network. Many people find this an easier way to apply updates. To use Red Hat Network, launch the Red Hat Update Agent with the following command: up2date This will start an interactive process that will result in the appropriate RPMs being upgraded on your system. References: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2002-1160 http://www.redhat.com/support/wpapers/redhat/newpam/tinkering.html Keywords: cookies, pam_xauth, root -------------------------------------------------------------------------------- The listed packages are GPG signed by Red Hat, Inc. for security. Our key is available at: http://www.redhat.com/solutions/security/news/publickey.html#key You can verify each package and see who signed it with the following command: rpm --checksig -v filename If you only wish to verify that each package has not been corrupted or tampered with, examine only the md5sum with the following command: md5sum filename Note that you need RPM >= 3.0 to check GnuPG keys. The Red Hat security contact is security@redhat.com. More contact details at http://www.redhat.com/solutions/security/news/contact.html [***** End Red Hat Advisory RHSA-2003: 035-10 *****]
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