CVE-2016-8734

Apache Subversions mod_dontdothat module and HTTP clients 1.4.0 through 1.8.16, and 1.9.0 through 1.9.4 are vulnerable to a denial-of-service attack caused by exponential XML entity expansion. The attack can cause the targeted process to consume an excessive amount of CPU resources or memory.

Weakness

The product does not properly control the allocation and maintenance of a limited resource.

Affected Software

Potential Mitigations

• Mitigation of resource exhaustion attacks requires that the target system either:

• The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.

• The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/147.html
• https://cwe.mitre.org/data/definitions/227.html
• https://cwe.mitre.org/data/definitions/492.html

References

• http://www.debian.org/security/2017/dsa-3932
• http://www.securityfocus.com/bid/94588
• http://www.securitytracker.com/id/1037361
• https://lists.apache.org/thread.html/7798f5cda1b2a3c70db4be77694b12dec8fcc1a441b00009d44f0e09%40%3Cannounce.apache.org%3E
• https://subversion.apache.org/security/CVE-2016-8734-advisory.txt
• https://www.oracle.com/security-alerts/cpuoct2020.html
• http://www.debian.org/security/2017/dsa-3932
• http://www.securityfocus.com/bid/94588
• http://www.securitytracker.com/id/1037361
• https://lists.apache.org/thread.html/7798f5cda1b2a3c70db4be77694b12dec8fcc1a441b00009d44f0e09%40%3Cannounce.apache.org%3E
• https://subversion.apache.org/security/CVE-2016-8734-advisory.txt
• https://www.oracle.com/security-alerts/cpuoct2020.html