KVM Syscall Emulation Debugging access control

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6.1$0-$5k0.00

Summaryinfo

A vulnerability classified as critical was found in KVM. The impacted element is an unknown function of the component Syscall Emulation Debugging. Executing a manipulation can lead to access control. This vulnerability is tracked as CVE-2017-7518. The attack is restricted to local execution. No exploit exists. A patch should be applied to remediate this issue.

Detailsinfo

A vulnerability has been found in KVM (version unknown) and classified as critical. This vulnerability affects an unknown function of the component Syscall Emulation Debugging. The manipulation with an unknown input leads to a access control vulnerability. The CWE definition for the vulnerability is CWE-264. As an impact it is known to affect confidentiality, integrity, and availability.

The bug was discovered 06/22/2017. The weakness was disclosed 06/22/2017 by Prasad J Pandit with Red Hat as [PATCH] KVM: x86: fix singlestepping over syscall as confirmed patch (Mailing List). The advisory is available at spinics.net. This vulnerability was named CVE-2017-7518 since 04/05/2017. The exploitation appears to be easy. Local access is required to approach this attack. No form of authentication is required for a successful exploitation. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1068 by the MITRE ATT&CK project. The advisory points out:

TF is handled a bit differently for syscall and sysret, compared to the other instructions: TF is checked after the instruction completes, so that the OS can disable #DB at a syscall by adding TF to FMASK. When the sysret is executed the #DB is taken "as if" the syscall insn just completed. KVM emulates syscall so that it can trap 32-bit syscall on Intel processors. Fix the behavior, otherwise you could get #DB on a user stack which is not nice. This does not affect Linux guests, as they use an IST or task gate for #DB.

The vulnerability scanner Nessus provides a plugin with the ID 109008 (Oracle Linux 6 / 7 : Unbreakable Enterprise kernel (ELSA-2018-4062)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Oracle Linux Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 351447 (Amazon Linux Security Advisory for kernel: ALAC2012-2018-013).

Applying a patch is able to eliminate this problem. The bugfix is ready for download at spinics.net. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Tenable (109008), SecurityFocus (BID 99263†) and SecurityTracker (ID 1038782†). The entries VDB-103034, VDB-104449, VDB-104864 and VDB-105193 are pretty similar. If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.2
VulDB Meta Temp Score: 6.1

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.8
NVD Vector: 🔍

CNA Base Score: 5.5
CNA Vector (Red Hat, Inc.): 🔍

CVSSv2info

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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
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NVD Base Score: 🔍

Exploitinginfo

Class: Access control
CWE: CWE-264
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 109008
Nessus Name: Oracle Linux 6 / 7 : Unbreakable Enterprise kernel (ELSA-2018-4062)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 53754
OpenVAS Name: Debian Security Advisory DSA 3981-1 (linux - security update)
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
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Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

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

Patch: spinics.net

Timelineinfo

04/05/2017 🔍
06/22/2017 +78 days 🔍
06/22/2017 +0 days 🔍
06/22/2017 +0 days 🔍
06/23/2017 +1 days 🔍
06/23/2017 +0 days 🔍
06/26/2017 +3 days 🔍
04/12/2018 +290 days 🔍
07/30/2018 +108 days 🔍
12/09/2022 +1593 days 🔍

Sourcesinfo

Advisory: [PATCH] KVM: x86: fix singlestepping over syscall
Researcher: Prasad J Pandit
Organization: Red Hat
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2017-7518 (🔍)
GCVE (CVE): GCVE-0-2017-7518
GCVE (VulDB): GCVE-100-102802

OVAL: 🔍

SecurityFocus: 99263 - Linux Kernel CVE-2017-7518 Privilage Escalation Vulnerability
SecurityTracker: 1038782

See also: 🔍

Entryinfo

Created: 06/26/2017 09:07
Updated: 12/09/2022 07:56
Changes: 06/26/2017 09:07 (78), 10/20/2019 12:19 (7), 12/29/2020 16:41 (2), 12/29/2020 16:46 (1), 12/09/2022 07:56 (12)
Complete: 🔍
Cache ID: 216:C82:103

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

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