CVE-2015-2313

Sandstorm Capn Proto before 0.4.1.1 and 0.5.x before 0.5.1.2, when an application invokes the totalSize method on an object reader, allows remote peers to cause a denial of service (CPU consumption) via a crafted small message, which triggers a tight for loop. NOTE: this vulnerability exists because of an incomplete fix for CVE-2015-2312.

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/2015/03/17/3
• https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=780568
• https://github.com/capnproto/capnproto/blob/master/security-advisories/2015-03-05-0-c%2B%2B-addl-cpu-amplification.md
• https://github.com/capnproto/capnproto/commit/80149744bdafa3ad4eedc83f8ab675e27baee868
• http://www.openwall.com/lists/oss-security/2015/03/17/3
• https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=780568
• https://github.com/capnproto/capnproto/blob/master/security-advisories/2015-03-05-0-c%2B%2B-addl-cpu-amplification.md
• https://github.com/capnproto/capnproto/commit/80149744bdafa3ad4eedc83f8ab675e27baee868