MIT Kerberos (krb5) seteuid() ftpd and ksu privilege escalation

kerberos-seteuid-privilege-escalation (28379) The risk level is classified as MediumMedium Risk

Description:

MIT Kerberos could allow a local attacker to gain elevated privileges on the system. The ftpd and ksu applications, which are included in the Kerberos source distribution, make unchecked seteuid() system calls. An attacker could exploit these vulnerabilities to read, write, create or delete arbitrary files with root privileges.

Platforms Affected:

  • Canonical, Ubuntu 5.04
  • Canonical, Ubuntu 5.10
  • Canonical, Ubuntu 6.06 LTS
  • Debian, Debian Linux 3.1
  • Gentoo, Linux
  • Heimdal Developers, Heimdal 0.7.2 and prior
  • MIT, Kerberos 5-1.4
  • MIT, Kerberos 5-1.4.1
  • MIT, Kerberos 5-1.4.2
  • MIT, Kerberos 5-1.4.3
  • MIT, Kerberos 5-1.5
  • RedHat, Enterprise Linux 4 Desktop
  • RedHat, Enterprise Linux 4 WS
  • RedHat, Enterprise Linux 4 ES
  • RedHat, Enterprise Linux 4 AS

Remedy:

Upgrade to the latest version of Kerberos (krb5-1.5.1 or later) or (krb5-1.4.4 or later), as listed in MIT krb5 Security Advisory 2006-001. See References.

—OR—

Apply the appropriate patch for your system, as listed in MIT krb5 Security Advisory 2006-001. See References.

For Heimdal:
Apply the patch for this vulnerability, as listed in Heimdal Security Advisory 2006-08-08. See References.

For Debian GNU/Linux:
Refer to DSA-1146-1 for patch, upgrade, or suggested workaround information. See References.

For Red Hat:
Refer to RHSA-2006:0612-8 for patch, upgrade, or suggested workaround information. See References.

For Gentoo Linux:
Refer to Gentoo Linux Security Announcement GLSA 200608-15 for patch, upgrade, or suggested workaround information. See References.

For Gentoo Linux (Heimdal):
Refer to Gentoo Linux Security Announcement GLSA 200608-21 for patch, upgrade, or suggested workaround information. See References.

For other distributions:
Contact your vendor for patch or upgrade information.

Consequences:

Gain Privileges

References:

  • Heimdal Security Advisory, 2006-08-08: multiple local privilege escalation vulnerabilities at http://www.pdc.kth.se/heimdal/advisory/2006-08-08/.
  • Kerberos Web site, Kerberos: The Network Authentication Protocol at http://web.mit.edu/kerberos/www/.
  • MIT krb5 Security Advisory 2006-001, multiple local privilege escalation vulnerabilities at http://web.mit.edu/kerberos/advisories/MITKRB5-SA-2006-001-setuid.txt.
  • BID-19427: MIT Kerberos 5 Multiple Local Privilege Escalation Vulnerabilities
  • CVE-2006-3084: The (1) ftpd and (2) ksu programs in (a) MIT Kerberos 5 (krb5) up to 1.5, and 1.4.x before 1.4.4, and (b) Heimdal 0.7.2 and earlier, do not check return codes for setuid calls, which might allow local users to gain privileges by causing setuid to fail to drop privileges. NOTE: as of 20060808, it is not known whether an exploitable attack scenario exists for these issues.
  • DSA-1146: krb5 -- programming error
  • GLSA-200608-15: MIT Kerberos 5: Multiple local privilege escalation vulnerabilities
  • GLSA-200608-21: Heimdal: Multiple local privilege escalation vulnerabilities
  • OSVDB ID: 27871: MIT Kerberos 5 ftpd seteuid() Local Privilege Escalation
  • OSVDB ID: 27872: MIT Kerberos 5 ksu seteuid() Local Privilege Escalation
  • SA21402: Kerberos V5 setuid Security Issue
  • SA21436: Heimdal setuid Security Issue
  • SECTRACK ID: 1016664: Kerberos Application Flaws in Evaluating setuid/seteuid Calls May Let Local Users Gain Elevated Privileges
  • SUSE-SR:2006:020: SUSE Security Summary Report
  • US-CERT VU#401660: MIT Kerberos (krb5) ftpd and ksu do not properly validate seteuid() calls
  • USN-329-1: Thunderbird vulnerabilities
  • USN-334-1: krb5 vulnerabilities
  • VUPEN/ADV-2006-3225: Kerberos V5 setuid() and seteuid() Calls Handling Local Privilege Escalation Vulnerability

Reported:

Aug 08, 2006

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