Certificate authentication bypass in Apache HTTP Server

1) Client certificate authentication bypass

EUVDB-ID: #VU91

Risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2016-4979

CWE-ID: CWE-287 - Improper Authentication

Exploit availability: No

Description

The vulnerability allows a remote attacker to bypass client certificate authentication.

The vulnerability exists due to HTTP/2 certificate validation error. A remote unauthenticated attacker can bypass client certificate authentication and access web resources on the target system.

Systems using the mod_http2 module with activated h2 and h2c protocols in configuration are affected.

Successful exploitation of this vulnerability may result unauthorized access to resources on the web server.

Mitigation

Install the latest version of Apache HTTP Server 2.4.23, which resolves this vulnerability.

Vulnerable software versions

Apache HTTP Server: 2.4.17 - 2.4.20

Apache HTTP Server:

: 11.3

Oracle Enterprise Manager Ops Center: 12.1.4 - 12.3.2

CPE2.3

• cpe:2.3:a:apache_foundation:apache_http_server:2.4.17:*:*:*:*:*:*:*
• cpe:2.3:a:apache_foundation:apache_http_server:2.4.18:*:*:*:*:*:*:*
• cpe:2.3:a:apache_foundation:apache_http_server:2.4.20:*:*:*:*:*:*:*
• cpe:2.3:a:apache_foundation:apache_http_server::*:*:*:*:*:*:*
• cpe:2.3::::11.3:*:*:*:*:*:*:*
• cpe:2.3:a:oracle:oracle_enterprise_manager_ops_center:12.1.4:*:*:*:*:*:*:*
• cpe:2.3:a:oracle:oracle_enterprise_manager_ops_center:12.2.2:*:*:*:*:*:*:*
• cpe:2.3:a:oracle:oracle_enterprise_manager_ops_center:12.3.2:*:*:*:*:*:*:*

External links

https://www.apache.org/dist/httpd/CHANGES_2.4.23
https://www.oracle.com/technetwork/topics/security/bulletinoct2016-3090566.html
https://www.oracle.com/technetwork/security-advisory/cpuoct2016-2881722.html

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.