USN-1030-1: Kerberos vulnerabilities

Ubuntu Security Notice USN-1030-1

9th December, 2010

krb5 vulnerabilities

A security issue affects these releases of Ubuntu and its derivatives:

  • Ubuntu 10.10
  • Ubuntu 10.04 LTS
  • Ubuntu 9.10
  • Ubuntu 8.04 LTS
  • Ubuntu 6.06 LTS

Software description

  • krb5

Details

It was discovered that Kerberos did not properly determine the
acceptability of certain checksums. A remote attacker could use certain
checksums to alter the prompt message, modify a response to a Key
Distribution Center (KDC) or forge a KRB-SAFE message. (CVE-2010-1323)

It was discovered that Kerberos did not properly determine the
acceptability of certain checksums. A remote attacker could use certain
checksums to forge GSS tokens or gain privileges. This issue only affected
Ubuntu 9.10, 10.04 LTS and 10.10. (CVE-2010-1324)

It was discovered that Kerberos did not reject RC4 key-derivation
checksums. An authenticated remote user could use this issue to forge
AD-SIGNEDPATH or AD-KDC-ISSUED signatures and possibly gain privileges.
This issue only affected Ubuntu 10.04 LTS and 10.10. (CVE-2010-4020)

It was discovered that Kerberos did not properly restrict the use of TGT
credentials for armoring TGS requests. A remote authenticated user could
use this flaw to impersonate a client. This issue only affected Ubuntu
9.10. (CVE-2010-4021)

Update instructions

The problem can be corrected by updating your system to the following package version:

Ubuntu 10.10:
libkrb5-3 1.8.1+dfsg-5ubuntu0.2
Ubuntu 10.04 LTS:
libkrb5-3 1.8.1+dfsg-2ubuntu0.4
Ubuntu 9.10:
libkrb5-3 1.7dfsg~beta3-1ubuntu0.7
Ubuntu 8.04 LTS:
libkrb53 1.6.dfsg.3~beta1-2ubuntu1.6
Ubuntu 6.06 LTS:
libkrb53 1.4.3-5ubuntu0.12

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

In general, a standard system update will make all the necessary changes.

References

CVE-2010-1323, CVE-2010-1324, CVE-2010-4020, CVE-2010-4021