Fabrice Bellard QEMU bits_per_pixel access control

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CTI Interest Score
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5.0$0-$5k0.00

Summaryinfo

A vulnerability has been found in Fabrice Bellard QEMU and classified as problematic. Affected is the function bits_per_pixel. This manipulation causes access control. This vulnerability is registered as CVE-2014-7815. No exploit is available. To fix this issue, it is recommended to deploy a patch.

Detailsinfo

A vulnerability was found in Fabrice Bellard QEMU (Virtualization Software) (the affected version unknown). It has been declared as problematic. Affected by this vulnerability is the function bits_per_pixel. 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 availability. The summary by CVE is:

The set_pixel_format function in ui/vnc.c in QEMU allows remote attackers to cause a denial of service (crash) via a small bytes_per_pixel value.

The weakness was published 11/10/2014 by Petr Matousek as vnc: sanitize bits_per_pixel from the client as confirmed patch (Mailing List). It is possible to read the advisory at lists.gnu.org. This vulnerability is known as CVE-2014-7815 since 10/03/2014. The attack needs to be done within the local network. A single authentication is necessary for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1068 according to MITRE ATT&CK. The advisory points out:

bits_per_pixel that are less than 8 could result in accessing non-initialized buffers later in the code due to the expectation that bytes_per_pixel value that is used to initialize these buffers is never zero.

The vulnerability scanner Nessus provides a plugin with the ID 81891 (CentOS 7 : qemu-kvm (CESA-2015:0349)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family CentOS Local Security Checks. The commercial vulnerability scanner Qualys is able to test this issue with plugin 168775 (SUSE Enterprise Linux Security update for xen (SUSE-SU-2016:1154-1)).

Applying a patch is able to eliminate this problem. A possible mitigation has been published immediately after the disclosure of the vulnerability. The vulnerability will be addressed with the following lines of code:

switch(bits_per_pixel) {
case 8:
case 16:
case 32:
    break;
default:
    vnc_client_error(vs);
    return;
    break;
}
The patch contains the following remark:
To fix this check that bits_per_pixel from the client is one of the values that the rfb protocol specification allows.
Furthermore it is possible to detect and prevent this kind of attack with TippingPoint and the filter 17163.

The vulnerability is also documented in the databases at X-Force (98577), Tenable (81891), SecurityFocus (BID 70998†), Secunia (SA61484†) and Vulnerability Center (SBV-50593†). Similar entries are available at VDB-13216, VDB-13276, VDB-13279 and VDB-13280. Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.7
VulDB Meta Temp Score: 5.0

VulDB Base Score: 5.7
VulDB Temp Score: 5.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

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

NVD Base Score: 🔍

Exploitinginfo

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

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Unproven

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 81891
Nessus Name: CentOS 7 : qemu-kvm (CESA-2015:0349)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍

OpenVAS ID: 703066
OpenVAS Name: Debian Security Advisory DSA 3066-1 (qemu - security update)
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: 🔍

Patch: e6908bfe8e07f2b452e78e677da1b45b1c0f6829
TippingPoint: 🔍

McAfee IPS: 🔍
McAfee IPS Version: 🔍

Fortigate IPS: 🔍

Timelineinfo

10/03/2014 🔍
11/06/2014 +34 days 🔍
11/10/2014 +4 days 🔍
11/10/2014 +0 days 🔍
11/11/2014 +1 days 🔍
11/12/2014 +1 days 🔍
11/14/2014 +2 days 🔍
04/14/2015 +151 days 🔍
06/17/2015 +64 days 🔍
02/24/2022 +2444 days 🔍

Sourcesinfo

Vendor: bellard.org

Advisory: vnc: sanitize bits_per_pixel from the client
Researcher: Petr Matousek
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2014-7815 (🔍)
GCVE (CVE): GCVE-0-2014-7815
GCVE (VulDB): GCVE-100-68155

OVAL: 🔍

X-Force: 98577 - QEMU bits_per_pixel denial of service, Medium Risk
SecurityFocus: 70998 - QEMU CVE-2014-7815 Local Denial of Service Vulnerability
Secunia: 61484 - QEMU VNC bits_per_pixel Handling Denial of Service Vulnerability, Less Critical
Vulnerability Center: 50593 - QEMU Remote DoS via a Small bytes_per_pixel value, Medium

See also: 🔍

Entryinfo

Created: 11/12/2014 16:32
Updated: 02/24/2022 13:12
Changes: 11/12/2014 16:32 (84), 06/30/2017 19:44 (5), 02/24/2022 13:06 (4), 02/24/2022 13:12 (1)
Complete: 🔍
Cache ID: 216::103

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