Security Bulletin: Potential SSL/TLS-related denial of service vulnerability in IBM Informix Server (CVE-2013-6329)

Summary

Informix Server is impacted by a vulnerability in IBM’s GSKIT library which can result in a denial of service caused by an error in SSL/TLS handshake processing related to session resumption when using SSLv2. A remote attacker could exploit this vulnerability to cause the system to crash.

Vulnerability Details

CVE ID: CVE-2013-6329

CVSS:

CVSS Base Score: 7.8

CVSS Temporal Score: See <https://exchange.xforce.ibmcloud.com/vulnerabilities/88939&gt; for the current score

CVSS Environmental Score*: Undefined

CVSS Vector: (AV:N/AC:L/Au:N/C:N/I:N/A:C)

Affected Products and Versions

Informix Server 11.50, 11.70 and 12.10

Remediation/Fixes

Product

| Remediation/First Fix
—|—
Informix Server 12.10| Upgrade to 12.10.xC3 or download and install GSKit (see next section)
Informix Server 11.70| Upgrade to 11.70.xC8 or download and install GSKit (see next section)
Informix Server 11.50| Upgrade and install GSKit (see next section)

Upgrading GSKit:

1. Download the appropriate GSKit using the following table:
   Product|Required GSKit version|GSKit link
   —|—|—
   Informix Server 12.10

Informix Server 11.70 (all platforms other than HP-UX PA-RISC)| 8.0.50.13| AIX (pSeries_32, pSeries_64)
HP-UX (Itanium_32, Itanium_64)
Linux (x86_32, x86_64, pSeries_64, zSeries_32, zSeries_64)
Solaris (SPARC_32, SPARC_64, x86_32, x86_64)
Windows (x86_32, x86_64)
Informix Server 11.70 (HP-UX PA-RISC platforms only)| 7.0.4.47| HP-UX (PA-RISC_32, PA-RISC_64)
Informix Server 11.50| 7.0.4.47| AIX (pSeries_32, pSeries_64)
HP-UX (Itanium_32, Itanium_64, PA-RISC_32, PA-RISC_64)
Linux (x86_32, x86_64, pSeries_64, zSeries_32, zSeries_64)
Solaris (SPARC_32, SPARC_64, x86_32, x86_64)
Windows (x86_32, x86_64)
2. Unix/Linux instructions:
1. Copy the downloaded tar file(s) to $INFORMIXDIR/gskit. Note: the old gskit .tar files must be removed or renamed to not end in .tar.
2. Bring the database server offline. (e.g. onmode -ky).
3. Change to the GSKit directory (cd $INFORMIXDIR/gskit).
4. As root, run “./installgskit”.
5. To verify the installation, run the appropriate command (i.e. gsk7ver, gsk7ver_64, gsk8ver or gsk8ver_64) for the GSKit you installed. The new version should be 7.0.4.47 or 8.0.50.13.
3. Windows GSkit version 7 x86_32 instructions:
1. Copy/download the gsk7d_7.0.4.47_win32.exe file to C:\tmp.
2. Start the ‘cmd’ program.
3. Change to the C:\temp directory (cd c:\tmp).
4. Run “gsk7d_7.0.4.47_win32.exe /D tmp”. This will extract the files to the C:\tmp\tmp directory.
5. Change to the C:\tmp\tmp directory (cd C:\tmp\tmp).
6. Run “setup GSK7BAS”. Accept all of the defaults.
7. To verify the installation, run gsk7ver to verify the installation. The new version should be 7.0.4.47.
4. All other Windows versions instructions:
1. Copy/download the appropriate file (gsk7d_7.0.4.47_win64.msi, gsk8ssl32.exe or gsk8ssl64.exe) to C:\tmp.
2. Using Windows Explorer, double click on the downloaded file. This will start Install Shield. Accept all of the defaults.
3. To verify the installation, run the appropriate command (i.e. gsk7ver_64, gsk8ver or gsk8ver_64) for the GSKit you installed. The new version should be 7.0.4.47 or 8.0.50.13.

Workarounds and Mitigations

Disable SSLV3 Session Cache (Note: This may cause performance problems):

* set GSK_V3_SIDCACHE_SIZE=0 in the environment