Debian Security Advisory

DSA-1571-1 openssl -- predictable random number generator

Date Reported:
13 May 2008
Affected Packages:
Security database references:
In Mitre's CVE dictionary: CVE-2008-0166.
More information:

Luciano Bello discovered that the random number generator in Debian's openssl package is predictable. This is caused by an incorrect Debian-specific change to the openssl package (CVE-2008-0166). As a result, cryptographic key material may be guessable.

This is a Debian-specific vulnerability which does not affect other operating systems which are not based on Debian. However, other systems can be indirectly affected if weak keys are imported into them.

It is strongly recommended that all cryptographic key material which has been generated by OpenSSL versions starting with 0.9.8c-1 on Debian systems is recreated from scratch. Furthermore, all DSA keys ever used on affected Debian systems for signing or authentication purposes should be considered compromised; the Digital Signature Algorithm relies on a secret random value used during signature generation.

The first vulnerable version, 0.9.8c-1, was uploaded to the unstable distribution on 2006-09-17, and has since that date propagated to the testing and current stable (etch) distributions. The old stable distribution (sarge) is not affected.

Affected keys include SSH keys, OpenVPN keys, DNSSEC keys, and key material for use in X.509 certificates and session keys used in SSL/TLS connections. Keys generated with GnuPG or GNUTLS are not affected, though.

A detector for known weak key material will be published at: (OpenPGP signature)

Instructions how to implement key rollover for various packages will be published at:

This web site will be continuously updated to reflect new and updated instructions on key rollovers for packages using SSL certificates. Popular packages not affected will also be listed.

In addition to this critical change, two other vulnerabilities have been fixed in the openssl package which were originally scheduled for release with the next etch point release: OpenSSL's DTLS (Datagram TLS, basically SSL over UDP) implementation did not actually implement the DTLS specification, but a potentially much weaker protocol, and contained a vulnerability permitting arbitrary code execution (CVE-2007-4995). A side channel attack in the integer multiplication routines is also addressed (CVE-2007-3108).

For the stable distribution (etch), these problems have been fixed in version 0.9.8c-4etch3.

For the unstable distribution (sid) and the testing distribution (lenny), these problems have been fixed in version 0.9.8g-9.

We recommend that you upgrade your openssl package and subsequently regenerate any cryptographic material, as outlined above.

Fixed in:

Debian GNU/Linux 4.0 (etch)

HP Precision:
Intel IA-32:
Intel IA-64:
Big-endian MIPS:
Little-endian MIPS:
IBM S/390:
Sun Sparc:

MD5 checksums of the listed files are available in the original advisory.