CVE-2016-9643

The regex code in Webkit 2.4.11 allows remote attackers to cause a denial of service (memory consumption) as demonstrated in a large number of ($ (open parenthesis and dollar) followed by {-2,16} and a large number of +) (plus close parenthesis).

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.openwall.com/lists/oss-security/2016/11/26/2
• http://www.openwall.com/lists/oss-security/2016/11/26/5
• http://www.securityfocus.com/bid/94559
• http://www.securitytracker.com/id/1038137
• https://security.gentoo.org/glsa/201706-15
• http://www.openwall.com/lists/oss-security/2016/11/26/2
• http://www.openwall.com/lists/oss-security/2016/11/26/5
• http://www.securityfocus.com/bid/94559
• http://www.securitytracker.com/id/1038137
• https://security.gentoo.org/glsa/201706-15