Xen up to 4.9.x __gnttab_cache_flush null pointer dereference

CVSS Meta Temp Score
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4.9$0-$5k0.00

Summaryinfo

A vulnerability has been found in Xen up to 4.9.x and classified as problematic. The affected element is the function __gnttab_cache_flush. Performing a manipulation results in null pointer dereference. This vulnerability is identified as CVE-2017-14318. The attack is only possible with local access. There is not any exploit available. It is recommended to apply a patch to fix this issue.

Detailsinfo

A vulnerability was found in Xen up to 4.9.x (Virtualization Software). It has been classified as problematic. This affects the function __gnttab_cache_flush. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. The summary by CVE is:

An issue was discovered in Xen 4.5.x through 4.9.x. The function `__gnttab_cache_flush` handles GNTTABOP_cache_flush grant table operations. It checks to see if the calling domain is the owner of the page that is to be operated on. If it is not, the owner's grant table is checked to see if a grant mapping to the calling domain exists for the page in question. However, the function does not check to see if the owning domain actually has a grant table or not. Some special domains, such as `DOMID_XEN`, `DOMID_IO` and `DOMID_COW` are created without grant tables. Hence, if __gnttab_cache_flush operates on a page owned by these special domains, it will attempt to dereference a NULL pointer in the domain struct.

The bug was discovered 09/12/2017. The weakness was released 09/12/2017 by Matthew Daley as XSA-232 as confirmed security advisory (Website). It is possible to read the advisory at xenbits.xen.org. This vulnerability is uniquely identified as CVE-2017-14318 since 09/12/2017. The exploitability is told to be easy. Attacking locally is a requirement. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 103381 (Citrix XenServer Multiple Vulnerabilities (CTX227185)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Misc. and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 170341 (SUSE Enterprise Linux Security Update for xen (SUSE-SU-2017:2420-1)).

Applying a patch is able to eliminate this problem. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Tenable (103381) and SecurityFocus (BID 100817†). Entries connected to this vulnerability are available at VDB-106429, VDB-106430 and VDB-106432. Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
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CVSSv3info

VulDB Meta Base Score: 5.1
VulDB Meta Temp Score: 5.1

VulDB Base Score: 3.8
VulDB Temp Score: 3.7
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 6.5
NVD Vector: 🔍

CVSSv2info

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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
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Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: No

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 103381
Nessus Name: Citrix XenServer Multiple Vulnerabilities (CTX227185)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 867773
OpenVAS Name: Fedora Update for xen FEDORA-2017-e399a9008c
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍

Timelineinfo

09/12/2017 🔍
09/12/2017 +0 days 🔍
09/12/2017 +0 days 🔍
09/12/2017 +0 days 🔍
09/12/2017 +0 days 🔍
09/12/2017 +0 days 🔍
09/13/2017 +1 days 🔍
09/21/2017 +8 days 🔍
01/11/2021 +1208 days 🔍

Sourcesinfo

Advisory: XSA-232
Researcher: Matthew Daley
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2017-14318 (🔍)
GCVE (CVE): GCVE-0-2017-14318
GCVE (VulDB): GCVE-100-106431

OVAL: 🔍

SecurityFocus: 100817 - Xen 'grant_table.c' Privilege Escalation Vulnerability
SecurityTracker: 1039349

See also: 🔍

Entryinfo

Created: 09/13/2017 10:55
Updated: 01/11/2021 16:52
Changes: 09/13/2017 10:55 (70), 11/15/2019 08:58 (12), 01/11/2021 16:52 (2)
Complete: 🔍
Cache ID: 216::103

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