CVE-2018-7540

An issue was discovered in Xen through 4.10.x allowing x86 PV guest OS users to cause a denial of service (host OS CPU hang) via non-preemptable L3/L4 pagetable freeing.

Weakness

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

Affected Software

Name	Vendor	Start Version	End Version
Xen	Xen	*	4.10.0 (including)
Xen	Ubuntu	artful	*
Xen	Ubuntu	cosmic	*
Xen	Ubuntu	disco	*
Xen	Ubuntu	eoan	*
Xen	Ubuntu	esm-infra/xenial	*
Xen	Ubuntu	groovy	*
Xen	Ubuntu	hirsute	*
Xen	Ubuntu	impish	*
Xen	Ubuntu	trusty	*
Xen	Ubuntu	upstream	*
Xen	Ubuntu	xenial	*

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.

NVD	https://nvd.nist.gov/vuln/detail/CVE-2018-7540
CWE	https://cwe.mitre.org/data/definitions/400.html

Uncontrolled Resource Consumption

Weakness

Affected Software

Potential Mitigations

References

CVE-2018-7540

Uncontrolled Resource Consumption

Weakness

Affected Software

Potential Mitigations

Related Attack Patterns

References