Vulnerability Assessment & Network Security Forums
If through a vulnerability assessment, a network security issue is detected for the vulnerability below, applying the appropriate security patches in a timely matter is very important. If you have detected that your system has already been compromised, following CERT's Network Security recovery document will assist with recommended steps for system recovery.
Vulnerability Assessment Details
Check for the version of the gnupg packages
Detailed Explanation for this Vulnerability Assessment
Updated gnupg packages are now available for Red Hat Enterprise Linux.
These updates disable the ability to generate ElGamal keys (used for both
signing and encrypting) and disable the ability to use ElGamal public keys
for encrypting data.
GnuPG is a utility for encrypting data and creating digital signatures.
Phong Nguyen identified a severe bug in the way GnuPG creates and uses
ElGamal keys, when those keys are used both to sign and encrypt data. This
vulnerability can be used to trivially recover the private key. While the
default behavior of GnuPG when generating keys does not lead to the
creation of unsafe keys, by overriding the default settings an unsafe key
could have been created.
If you are using ElGamal keys, you should revoke those keys immediately.
The packages included in this update do not make ElGamal keys safe to use
they merely include a patch by David Shaw that disables functions that
would generate or use ElGamal keys.
To acertain if your key is affected, run the following command to obtain a
list of secret keys that you have on your secret keyring:
The output of this command includes both the size and type of the keys
found, and will look similar to this example:
sec 1024D/01234567 2000-10-17 Example User
uid Example User
The key length, type, and ID are listed together, separated by a forward
slash. In the example output above, the key's type is "D" (DSA, sign
and encrypt). Your key is unsafe if and only if the key type is "G"
(ElGamal, sign and encrypt). In the above example, the secret key is safe
to use, while the secret key in the following example is not:
sec 1024G/01234567 2000-10-17 Example User
uid Example User
For more details regarding this issue, as well as instructions on how to
revoke any keys that are unsafe, refer to the advisory available from the
GnuPG web site:
Solution : http://rhn.redhat.com/errata/RHSA-2003-395.html
Network Security Threat Level: High
Networks Security ID:
Vulnerability Assessment Copyright: This script is Copyright (C) 2004 Tenable Network Security
|Cisco IronPort C160 Email Security Appliance
|Sophos UTM 110/120/100 Rev. 5 Firewall Security Router w/power adapter
|ZyXel ZyWall USG 100 Unified Security Gateway Firewall w/ Rackmounts
|Cisco ASA 5545-X V01 8-Port Firewall Security Appliance - Tested #28767
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