Xen up to 4.12.x Hypercall p2m_resolve_translation_fault input validation
CVSS Meta Temp Score | Current Exploit Price (≈) | CTI Interest Score |
---|---|---|
6.5 | $0-$5k | 0.00 |
A vulnerability was found in Xen up to 4.12.x (Virtualization Software). It has been declared as problematic. Affected by this vulnerability is the function p2m_resolve_translation_fault
of the component Hypercall Handler. The manipulation with an unknown input 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. The summary by CVE is:
An issue was discovered in Xen through 4.12.x allowing ARM guest OS users to cause a denial of service via a XENMEM_add_to_physmap hypercall. p2m->max_mapped_gfn is used by the functions p2m_resolve_translation_fault() and p2m_get_entry() to sanity check guest physical frame. The rest of the code in the two functions will assume that there is a valid root table and check that with BUG_ON(). The function p2m_get_root_pointer() will ignore the unused top bits of a guest physical frame. This means that the function p2m_set_entry() will alias the frame. However, p2m->max_mapped_gfn will be updated using the original frame. It would be possible to set p2m->max_mapped_gfn high enough to cover a frame that would lead p2m_get_root_pointer() to return NULL in p2m_get_entry() and p2m_resolve_translation_fault(). Additionally, the sanity check on p2m->max_mapped_gfn is off-by-one allowing "highest mapped + 1" to be considered valid. However, p2m_get_root_pointer() will return NULL. The problem could be triggered with a specially crafted hypercall XENMEM_add_to_physmap{, _batch} followed by an access to an address (via hypercall or direct access) that passes the sanity check but cause p2m_get_root_pointer() to return NULL. A malicious guest administrator may cause a hypervisor crash, resulting in a Denial of Service (DoS). Xen version 4.8 and newer are vulnerable. Only Arm systems are vulnerable. x86 systems are not affected.
The weakness was shared 10/31/2019 (oss-sec). The advisory is shared at openwall.com. This vulnerability is known as CVE-2019-18423 since 10/24/2019. The attack can be launched remotely. The requirement for exploitation is a single authentication. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k 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.
The entries 144711, 144710, 144708 and 144707 are related to this item.
Product
Type
Name
Version
License
CPE 2.3
CPE 2.2
CVSSv4
VulDB CVSS-B Score: 🔍VulDB CVSS-BT Score: 🔍
VulDB Vector: 🔍
VulDB Reliability: 🔍
CVSSv3
VulDB Meta Base Score: 6.5VulDB Meta Temp Score: 6.5
VulDB Base Score: 4.3
VulDB Temp Score: 4.3
VulDB Vector: 🔍
VulDB Reliability: 🔍
NVD Base Score: 8.8
NVD Vector: 🔍
CVSSv2
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍
NVD Base Score: 🔍
Exploiting
Class: Input validationCWE: CWE-20
CAPEC: 🔍
ATT&CK: 🔍
Local: No
Remote: Yes
Availability: 🔍
Status: Not defined
EPSS Score: 🔍
EPSS Percentile: 🔍
Price Prediction: 🔍
Current Price Estimation: 🔍
0-Day | unlock | unlock | unlock | unlock |
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Threat Intelligence
Interest: 🔍Active Actors: 🔍
Active APT Groups: 🔍
Countermeasures
Recommended: no mitigation knownStatus: 🔍
0-Day Time: 🔍
Timeline
10/24/2019 🔍10/31/2019 🔍
11/01/2019 🔍
02/01/2024 🔍
Sources
Advisory: FEDORA-2019-376ec5c107Status: Not defined
CVE: CVE-2019-18423 (🔍)
See also: 🔍
Entry
Created: 11/01/2019 07:20Updated: 02/01/2024 09:49
Changes: 11/01/2019 07:20 (38), 11/01/2019 07:25 (18), 02/01/2024 09:49 (3)
Complete: 🔍
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