Xen 4.7.x/4.8.x/4.9.x/4.10.x libxl information disclosure

CVSS Meta Temp Score
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CTI Interest Score
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8.5$0-$5k0.00

Summaryinfo

A vulnerability classified as critical has been found in Xen 4.7.x/4.8.x/4.9.x/4.10.x. Impacted is an unknown function of the component libxl. Performing a manipulation results in information disclosure. This vulnerability is reported as CVE-2018-12892. The attack is possible to be carried out remotely. No exploit exists. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Xen 4.7.x/4.8.x/4.9.x/4.10.x (Virtualization Software). It has been classified as critical. This affects some unknown processing of the component libxl. The manipulation with an unknown input leads to a information disclosure vulnerability. CWE is classifying the issue as CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

An issue was discovered in Xen 4.7 through 4.10.x. libxl fails to pass the readonly flag to qemu when setting up a SCSI disk, due to what was probably an erroneous merge conflict resolution. Malicious guest administrators or (in some situations) users may be able to write to supposedly read-only disk images. Only emulated SCSI disks (specified as "sd" in the libxl disk configuration, or an equivalent) are affected. IDE disks ("hd") are not affected (because attempts to make them readonly are rejected). Additionally, CDROM devices (that is, devices specified to be presented to the guest as CDROMs, regardless of the nature of the backing storage on the host) are not affected; they are always read only. Only systems using qemu-xen (rather than qemu-xen-traditional) as the device model version are vulnerable. Only systems using libxl or libxl-based toolstacks are vulnerable. (This includes xl, and libvirt with the libxl driver.) The vulnerability is present in Xen versions 4.7 and later. (In earlier versions, provided that the patch for XSA-142 has been applied, attempts to create read only disks are rejected.) If the host and guest together usually support PVHVM, the issue is exploitable only if the malicious guest administrator has control of the guest kernel or guest kernel command line.

The bug was discovered 06/27/2018. The weakness was disclosed 07/02/2018 by Andrew (Website). It is possible to read the advisory at openwall.com. This vulnerability is uniquely identified as CVE-2018-12892 since 06/26/2018. The exploitability is told to be easy. It is possible to initiate the attack remotely. Required for exploitation is a authentication. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1592 according to MITRE ATT&CK.

The vulnerability was handled as a non-public zero-day exploit for at least 5 days. During that time the estimated underground price was around $5k-$25k. The vulnerability scanner Nessus provides a plugin with the ID 111348 (SUSE SLED12 / SLES12 Security Update : xen (SUSE-SU-2018:2059-1)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family SuSE Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 176419 (Debian Security Update for xen (DSA 4236-1)).

Upgrading eliminates this vulnerability. A possible mitigation has been published 4 weeks after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Tenable (111348) and SecurityFocus (BID 104571†). The entries VDB-119508, VDB-120119, VDB-120120 and VDB-120121 are pretty similar. Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.6
VulDB Meta Temp Score: 8.5

VulDB Base Score: 7.4
VulDB Temp Score: 7.1
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 9.9
NVD Vector: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Information disclosure
CWE: CWE-200 / CWE-284 / CWE-266
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 111348
Nessus Name: SUSE SLED12 / SLES12 Security Update : xen (SUSE-SU-2018:2059-1)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

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

Timelineinfo

06/26/2018 🔍
06/27/2018 +1 days 🔍
06/27/2018 +0 days 🔍
07/02/2018 +4 days 🔍
07/02/2018 +0 days 🔍
07/03/2018 +1 days 🔍
07/25/2018 +22 days 🔍
07/26/2018 +1 days 🔍
03/29/2023 +1707 days 🔍

Sourcesinfo

Advisory: openwall.com
Researcher: Andrew
Status: Not defined
Confirmation: 🔍

CVE: CVE-2018-12892 (🔍)
GCVE (CVE): GCVE-0-2018-12892
GCVE (VulDB): GCVE-100-120147

OVAL: 🔍

SecurityFocus: 104571 - Xen CVE-2018-12892 Local Security Bypass Vulnerability
SecurityTracker: 1041203

See also: 🔍

Entryinfo

Created: 07/03/2018 08:33
Updated: 03/29/2023 15:00
Changes: 07/03/2018 08:33 (74), 02/23/2020 16:44 (7), 03/29/2023 15:00 (4)
Complete: 🔍
Cache ID: 216::103

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