Xen up to 4.12.x Hypercall hypercall_create_continuation Parameter input validation

Summaryinfo

A vulnerability, which was classified as problematic, was found in Xen up to 4.12.x. Affected by this issue is the function hypercall_create_continuation of the component Hypercall Handler. Executing a manipulation as part of Parameter can lead to input validation. This vulnerability is handled as CVE-2019-18420. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability has been found in Xen up to 4.12.x (Virtualization Software) and classified as problematic. This vulnerability affects the function hypercall_create_continuation of the component Hypercall Handler. The manipulation as part of a Parameter leads to a input validation vulnerability. The CWE definition for the vulnerability is CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. As an impact it is known to affect availability. CVE summarizes:

An issue was discovered in Xen through 4.12.x allowing x86 PV guest OS users to cause a denial of service via a VCPUOP_initialise hypercall. hypercall_create_continuation() is a variadic function which uses a printf-like format string to interpret its parameters. Error handling for a bad format character was done using BUG(), which crashes Xen. One path, via the VCPUOP_initialise hypercall, has a bad format character. The BUG() can be hit if VCPUOP_initialise executes for a sufficiently long period of time for a continuation to be created. Malicious guests may cause a hypervisor crash, resulting in a Denial of Service (DoS). Xen versions 4.6 and newer are vulnerable. Xen versions 4.5 and earlier are not vulnerable. Only x86 PV guests can exploit the vulnerability. HVM and PVH guests, and guests on ARM systems, cannot exploit the vulnerability.

The weakness was released 10/31/2019 (oss-sec). The advisory is available at openwall.com. This vulnerability was named CVE-2019-18420 since 10/24/2019. The attack can be initiated remotely. A single authentication is required for exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 02/01/2024).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Entries connected to this vulnerability are available at VDB-144710, VDB-144709, VDB-144708 and VDB-144707. If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

• Virtualization Software

Name

• Xen

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4
• 4.5
• 4.6
• 4.7
• 4.8
• 4.9
• 4.10
• 4.11
• 4.12

License

• open-source

CPE 2.3info

• 🔍
• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍
• 🔍

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Entryinfo

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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