Finding and Fixing Apache APR apr_palloc Heap Overflow, a High Risk Vulnerability

With Notes on Remediation, Penetration Testing, Disclosures, Patching and Exploits

Contents

  • Vital information on this issue
  • Scanning For and Finding Apache APR apr_palloc Heap Overflow
  • Penetration Testing (Pentest) for this Vulnerability
  • Security updates on Apache APR apr_palloc Heap Overflow
  • Disclosures related to Apache APR apr_palloc Heap Overflow
  • Confirming the Presence of Apache APR apr_palloc Heap Overflow
  • False positive/negatives
  • Patching/Repairing this vulnerability
  • Exploits related to Apache APR apr_palloc Heap Overflow

Vital Information on This Issue
Apache APR apr_palloc Heap Overflow is a high risk vulnerability that is one of the most frequently found on networks around the world. This issue has been around since at least 1990 but has proven either difficult to detect, difficult to resolve or prone to being overlooked entirely.


Vulnerability Name: Apache APR apr_palloc Heap Overflow
Test ID: 14301
Risk: High
Category: Web servers
Type: Attack
Summary: Multiple integer overflows in the Apache Portable Runtime (APR) library and the Apache Portable Utility library (aka APR-util) 0.9.x and 1.3.x allow remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via vectors that trigger crafted calls to the allocator_alloc or apr_palloc function in memory/unix/apr_pools.c in APR; or crafted calls to the apr_rmm_malloc, apr_rmm_calloc, or apr_rmm_realloc function in misc/apr_rmm.c in APR-util; leading to buffer overflows. NOTE: some of these details are obtained from third party information.
Impact: There is a total shutdown of the affected resource. The attacker can render the resource completely unavailable.
Solution: Upgrade to Apache version 2.2.13 or newer. https://www.cvedetails.com/vulnerability-list/vendor_id-45/product_id-66/version_id-80726/Apache-Http-Server-2.2.13.html
CVE: CVE-2009-2412
More Information: http://httpd.apache.org/security/vulnerabilities_22.html
Nist NVD (CVSS): AV:N/AC:L/Au:N/C:C/I:C/A:C
CVSS Score: 10.0
For more information on this also issue see: www.securiteam.com

Scanning For and Finding Apache APR apr_palloc Heap Overflow
Use of Vulnerability Management tools, like AVDS, are standard practice for the discovery of this vulnerability. The primary failure of VA in finding this vulnerability is related to setting the proper scope and frequency of network scans. It is vital that the broadest range of hosts (active IPs) possible are scanned and that scanning is done frequently. We recommend weekly. Your existing scanning solution or set of test tools should make this not just possible, but easy and affordable. If that is not the case, please consider AVDS.

Penetration Testing (pentest) for this Vulnerability
The Apache APR apr_palloc Heap Overflow is prone to false positive reports by most vulnerability assessment solutions. AVDS is alone in using behavior based testing that eliminates this issue. For all other VA tools security consultants will recommend confirmation by direct observation. In any case Penetration testing procedures for discovery of [name] produces the highest discovery accuracy rate, but the infrequency of this expensive form of testing degrades its value. The ideal would be to have pentesting accuracy and the frequency and scope possibilities of VA solutions, and this is accomplished only by AVDS.

Security Updates on Apache APR apr_palloc Heap Overflow
For the most current updates on this vulnerability please check www.securiteam.com Given that this is one of the most frequently found vulnerabilities, there is ample information regarding mitigation online and very good reason to get it fixed. Hackers are also aware that this is a frequently found vulnerability and so its discovery and repair is that much more important. It is so well known and common that any network that has it present and unmitigated indicates "low hanging fruit" to attackers.

Disclosures related to this vulnerability
http://seclists.org/fulldisclosure/2009/Dec/91

Confirming the Presence of Apache APR apr_palloc Heap Overflow
AVDS is currently testing for and finding this vulnerability with zero false positives. If your current set of tools is indicating that it is present but you think it is probably a false positive, please contact us for a demonstration of AVDS.

False positive/negatives
The secret killer of VA solution value is the false positive. There was an industry wide race to find the most vulnerabilities, including Apache APR apr_palloc Heap Overflow ,and this resulted in benefit to poorly written tests that beef up scan reports by adding a high percentage of uncertainty. This may have sold a lot of systems some years ago, but it also stuck almost all VA solutions with deliberately inaccurate reporting that adds time to repairs that no administrator can afford. Beyond Security did not participate in this race to mutually assured destruction of the industry and to this day produces the most accurate and actionable reports available.

Patching/Repairing this Vulnerability
http://httpd.apache.org/download.cgi Apache APR apr_palloc Heap Overflow is a high risk vulnerability that is also high frequency and high visibility. This is the most severe combination of security factors that exists and it is extremely important to find it on your network and fix it as soon as possible.

Exploits related to Apache APR apr_palloc Heap Overflow
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-1891
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-2412

Please also visit www.securiteam.com to view any exploits available for this vulnerability, or search using "Apache APR apr_palloc Heap Overflow exploits".


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