PHP up to 5.4.44/5.5.28/5.6.12 unserialize use after free

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
8.2$0-$5k0.00

Summaryinfo

A vulnerability categorized as critical has been discovered in PHP up to 5.4.44/5.5.28/5.6.12. This issue affects the function unserialize. Such manipulation leads to use after free. This vulnerability is listed as CVE-2015-6834. In addition, an exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in PHP up to 5.4.44/5.5.28/5.6.12 (Programming Language Software). Affected by this issue is the function unserialize. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability.

The weakness was presented 09/03/2015 as Version 5.6.13 as confirmed changelog entry (Website). The advisory is shared for download at secure.php.net. This vulnerability is handled as CVE-2015-6834 since 09/08/2015. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details as well as a public exploit are known.

A public exploit has been developed by SEC Consult and been published 2 years after the advisory. The exploit is available at exploit-db.com. It is declared as proof-of-concept. As 0-day the estimated underground price was around $5k-$25k. The vulnerability scanner Nessus provides a plugin with the ID 86794 (Debian DLA-341-1 : php5 security update), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Debian Local Security Checks. The commercial vulnerability scanner Qualys is able to test this issue with plugin 11628 (PHP Versions Prior to 5.6.13/5.5.29/5.4.45 Multiple Vulnerabilities).

Upgrading to version 5.4.45, 5.5.29 or 5.6.13 eliminates this vulnerability. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Exploit-DB (40414), Tenable (86794), SecurityFocus (BID 76649†) and SecurityTracker (ID 1033548†). See VDB-67396, VDB-67398, VDB-67420 and VDB-67631 for similar entries. Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.5
VulDB Meta Temp Score: 8.2

VulDB Base Score: 7.3
VulDB Temp Score: 6.6
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 9.8
NVD Vector: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

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

NVD Base Score: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Author: SEC Consult
Download: 🔍

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Nessus ID: 86794
Nessus Name: Debian DLA-341-1 : php5 security update
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍

OpenVAS ID: 14611
OpenVAS Name: Amazon Linux Local Check: alas-2016-670
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Exploit-DB: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

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

Upgrade: PHP 5.4.45/5.5.29/5.6.13

Timelineinfo

08/27/2015 🔍
09/03/2015 +7 days 🔍
09/03/2015 +0 days 🔍
09/08/2015 +5 days 🔍
09/14/2015 +6 days 🔍
09/16/2015 +2 days 🔍
05/16/2016 +243 days 🔍
09/22/2016 +129 days 🔍
09/22/2016 +0 days 🔍
01/04/2025 +3026 days 🔍

Sourcesinfo

Product: php.org

Advisory: Version 5.6.13
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2015-6834 (🔍)
GCVE (CVE): GCVE-0-2015-6834
GCVE (VulDB): GCVE-100-77708

OVAL: 🔍

SecurityFocus: 76649 - PHP CVE-2015-6834 Multiple Remote Code Execution Vulnerabilities
SecurityTracker: 1033548

scip Labs: https://www.scip.ch/en/?labs.20161013
See also: 🔍

Entryinfo

Created: 09/16/2015 11:27
Updated: 01/04/2025 14:24
Changes: 09/16/2015 11:27 (53), 12/19/2017 08:19 (28), 06/15/2022 13:45 (3), 06/15/2022 13:51 (11), 06/15/2022 13:57 (1), 01/04/2025 14:24 (14)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Want to know what is going to be exploited?

We predict KEV entries!