CVE-2005-2531: Medium severity OpenVPN OpenVPN vulnerability

Published Aug 24, 2005

Updated

OpenVPN before 2.0.1, when running with "verb 0" and without TLS authentication, does not properly flush the OpenSSL error queue when a client fails certificate authentication to the server and causes the error to be processed by the wrong client, which allows remote attackers to cause a denial of service (client disconnection) via a large number of failed authentication attempts.

Affected Software

74 affected components

OpenVPN OpenVPN=2.0

OpenVPN OpenVPN=2.0.1_rc1

OpenVPN OpenVPN=2.0.1_rc2

OpenVPN OpenVPN=2.0.1_rc3

OpenVPN OpenVPN=2.0.1_rc4

OpenVPN OpenVPN=2.0.1_rc5

OpenVPN OpenVPN=2.0.1_rc6

OpenVPN OpenVPN=2.0.1_rc7

OpenVPN OpenVPN=2.0_beta1

OpenVPN OpenVPN=2.0_beta2

OpenVPN OpenVPN=2.0_beta3

OpenVPN OpenVPN=2.0_beta4

OpenVPN OpenVPN=2.0_beta5

OpenVPN OpenVPN=2.0_beta6

OpenVPN OpenVPN=2.0_beta7

OpenVPN OpenVPN=2.0_beta8

OpenVPN OpenVPN=2.0_beta9

OpenVPN OpenVPN=2.0_beta10

OpenVPN OpenVPN=2.0_beta11

OpenVPN OpenVPN=2.0_beta12

OpenVPN OpenVPN=2.0_beta13

OpenVPN OpenVPN=2.0_beta15

OpenVPN OpenVPN=2.0_beta16

OpenVPN OpenVPN=2.0_beta17

OpenVPN OpenVPN=2.0_beta18

OpenVPN OpenVPN=2.0_beta19

OpenVPN OpenVPN=2.0_beta20

OpenVPN OpenVPN=2.0_beta28

OpenVPN OpenVPN=2.0_rc1

OpenVPN OpenVPN=2.0_rc2

OpenVPN OpenVPN=2.0_rc3

OpenVPN OpenVPN=2.0_rc4

OpenVPN OpenVPN=2.0_rc5

OpenVPN OpenVPN=2.0_rc6

OpenVPN OpenVPN=2.0_rc7

OpenVPN OpenVPN=2.0_rc8

OpenVPN OpenVPN=2.0_rc9

OpenVPN OpenVPN=2.0_rc10

OpenVPN OpenVPN=2.0_rc11

OpenVPN OpenVPN=2.0_rc12

OpenVPN OpenVPN=2.0_rc13

OpenVPN OpenVPN=2.0_rc14

OpenVPN OpenVPN=2.0_rc15

OpenVPN OpenVPN=2.0_rc16

OpenVPN OpenVPN=2.0_rc17

OpenVPN OpenVPN=2.0_rc18

OpenVPN OpenVPN=2.0_rc19

OpenVPN OpenVPN=2.0_rc20

OpenVPN OpenVPN=2.0_rc21

OpenVPN OpenVPN=2.0_test1

OpenVPN OpenVPN=2.0_test2

OpenVPN OpenVPN=2.0_test3

OpenVPN OpenVPN=2.0_test5

OpenVPN OpenVPN=2.0_test6

OpenVPN OpenVPN=2.0_test7

OpenVPN OpenVPN=2.0_test8

OpenVPN OpenVPN=2.0_test9

OpenVPN OpenVPN=2.0_test10

OpenVPN OpenVPN=2.0_test11

OpenVPN OpenVPN=2.0_test12

OpenVPN OpenVPN=2.0_test14

OpenVPN OpenVPN=2.0_test15

OpenVPN OpenVPN=2.0_test16

OpenVPN OpenVPN=2.0_test17

OpenVPN OpenVPN=2.0_test18

OpenVPN OpenVPN=2.0_test19

OpenVPN OpenVPN=2.0_test20

OpenVPN OpenVPN=2.0_test21

OpenVPN OpenVPN=2.0_test22

OpenVPN OpenVPN=2.0_test23

OpenVPN OpenVPN=2.0_test24

OpenVPN OpenVPN=2.0_test26

OpenVPN OpenVPN=2.0_test27

OpenVPN OpenVPN=2.0_test29

Remediation

Patch Available

http://www.mandriva.com/security/advisories?name=MDKSA-2005:145

Event History

Aug 24, 2005

CVE Published

04:00 AM

CVE Published

via MITRE·08:00 AM

Data Sourced

via MITRE·08:00 AM

Description

Frequently Asked Questions

What is the severity of CVE-2005-2531?

The severity of CVE-2005-2531 is considered high due to the potential for denial of service attacks.

How do I fix CVE-2005-2531?

To fix CVE-2005-2531, upgrade OpenVPN to version 2.0.1 or later.

What versions are affected by CVE-2005-2531?

CVE-2005-2531 affects OpenVPN versions 2.0 beta, rc, and test releases up to 2.0.1.

What causes the vulnerability in CVE-2005-2531?

The vulnerability in CVE-2005-2531 is caused by improper flushing of the OpenSSL error queue when client certificate authentication fails.

Who can exploit CVE-2005-2531?

Remote attackers can exploit CVE-2005-2531 to cause denial of service by targeting clients without proper TLS authentication.