Fabrice Bellard QEMU ui/vnc.c vnc_refresh_server_surface memory corruption

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CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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5.2$0-$5k0.00

A vulnerability classified as problematic was found in Fabrice Bellard QEMU (Virtualization Software) (the affected version is unknown). This vulnerability affects the function vnc_refresh_server_surface of the file ui/vnc.c. The manipulation with an unknown input leads to a memory corruption vulnerability. The CWE definition for the vulnerability is CWE-119. As an impact it is known to affect confidentiality, integrity, and availability.

The weakness was disclosed 09/14/2015 by Qinghao Tang as confirmed git commit (GIT Repository). The advisory is shared for download at git.qemu.org. This vulnerability was named CVE-2015-5225 since 07/01/2015. The exploitation appears to be easy. The attack needs to be approached locally. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 09/21/2018). Responsible for the vulnerability is the following code:

if ((x + 1) * cmp_bytes > min_stride) {
   _cmp_bytes = min_stride - x * cmp_bytes;

The vulnerability scanner Nessus provides a plugin with the ID 85774 (Fedora 23 : qemu-2.4.0-2.fc23 (2015-14783)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Fedora Local Security Checks and running in the context local. The commercial vulnerability scanner Qualys is able to test this issue with plugin 157511 (Oracle Enterprise Linux Security Update for qemu-kvm (ELSA-2017-1856)).

Applying a patch is able to eliminate this problem. The bugfix is ready for download at git.qemu.org. A possible mitigation has been published even before and not after the disclosure of the vulnerability. The vulnerability will be addressed with the following lines of code:

if ((x + 1) * cmp_bytes > line_bytes) {
   _cmp_bytes = line_bytes - x * cmp_bytes;

The vulnerability is also documented in the databases at SecurityFocus (BID 76506), X-Force (106397), Vulnerability Center (SBV-54401) and Tenable (85774).

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VulDB Meta Base Score: 5.9
VulDB Meta Temp Score: 5.2

VulDB Base Score: 5.9
VulDB Temp Score: 5.2
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2infoedit

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VulDB Base Score: 🔍
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Exploitinginfoedit

Class: Memory corruption
CWE: CWE-119
ATT&CK: Unknown

Local: Yes
Remote: No

Availability: 🔍
Status: Unproven

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 85774
Nessus Name: Fedora 23 : qemu-2.4.0-2.fc23 (2015-14783)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 703348
OpenVAS Name: Debian Security Advisory DSA 3348-1 (qemu - security update)
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfoedit

Threat: 🔍
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Countermeasuresinfoedit

Recommended: Patch
Status: 🔍

0-Day Time: 🔍

Patch: git.qemu.org

Timelineinfoedit

07/01/2015 🔍
08/22/2015 +51 days 🔍
08/22/2015 +0 days 🔍
09/04/2015 +13 days 🔍
09/04/2015 +0 days 🔍
09/14/2015 +10 days 🔍
09/18/2015 +4 days 🔍
11/06/2015 +49 days 🔍
11/14/2015 +8 days 🔍
09/09/2018 +1029 days 🔍
09/21/2018 +12 days 🔍

Sourcesinfoedit

Vendor: https://bellard.org/

Advisory: git.qemu.org
Researcher: Qinghao Tang
Status: Confirmed

CVE: CVE-2015-5225 (🔍)
OVAL: 🔍

SecurityFocus: 76506 - QEMU CVE-2015-5225 Heap Based Buffer Overflow Vulnerability
X-Force: 106397 - QEMU vnc_refresh_server_surface() buffer overflow
Vulnerability Center: 54401 - QEMU before 2.4.0.1 Remote Code Execution via the VNC Display Driver, High

Entryinfoedit

Created: 09/18/2015 11:26 AM
Updated: 09/21/2018 10:01 AM
Changes: (10) vulnerability_cvss2_nvd_av vulnerability_cvss2_nvd_ac vulnerability_cvss2_nvd_au vulnerability_cvss2_nvd_ci vulnerability_cvss2_nvd_ii vulnerability_cvss2_nvd_ai advisory_person_name countermeasure_date source_securityfocus_date source_securityfocus_class
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