libxml2 XML External Entity DOCTYPE access control

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5.1$0-$5k0.00

Summaryinfo

A vulnerability identified as problematic has been detected in libxml2. This vulnerability affects unknown code of the component XML External Entity Handler. The manipulation of the argument DOCTYPE with the input <!DOCTYPE external [<!ENTITY ee SYSTEM "file:///PATH/TO/simple.xml">]><root>&ee;</root> as part of XML File leads to access control. This vulnerability is referenced as CVE-2013-0339. No exploit is available. To fix this issue, it is recommended to deploy a patch.

Detailsinfo

A vulnerability was found in libxml2 (Document Processing Software) (affected version not known) and classified as problematic. This issue affects some unknown functionality of the component XML External Entity Handler. The manipulation of the argument DOCTYPE with the input value <!DOCTYPE external [<!ENTITY ee SYSTEM "file:///PATH/TO/simple.xml">]><root>&ee;</root> leads to a access control vulnerability. Using CWE to declare the problem leads to CWE-264. Impacted is confidentiality. The summary by CVE is:

libxml2 through 2.9.1 does not properly handle external entities expansion unless an application developer uses the xmlSAX2ResolveEntity or xmlSetExternalEntityLoader function, which allows remote attackers to cause a denial of service (resource consumption), send HTTP requests to intranet servers, or read arbitrary files via a crafted XML document, aka an XML External Entity (XXE) issue. NOTE: it could be argued that because libxml2 already provides the ability to disable external entity expansion, the responsibility for resolving this issue lies with application developers; according to this argument, this entry should be REJECTed and each affected application would need its own CVE.

The weakness was published 02/19/2013 by Kurt Seifried with Red Hat as CVEs for libxml2 and expat internal and external XML entity expansion as confirmed mailinglist post (oss-sec). It is possible to read the advisory at seclists.org. The public release has been coordinated with the project team. The identification of this vulnerability is CVE-2013-0339 since 12/06/2012. The attack may be initiated remotely. No form of authentication is needed for a successful 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. If entities expansion in the XML parser is asked for, it is possble to craft relatively small input document leading to excessive on-the-fly content generation. This can cause resources to be consumed or can result in port scanning/application scanning information being sent to the attacker.

The vulnerability scanner Nessus provides a plugin with the ID 68903 (Ubuntu 10.04 LTS / 12.04 LTS / 12.10 / 13.04 : libxml2 vulnerabilities (USN-1904-1)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Ubuntu Local Security Checks. The commercial vulnerability scanner Qualys is able to test this issue with plugin 195411 (Ubuntu Security Notification for Libxml2 Regression (USN-1904-2)).

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

The vulnerability is also documented in the databases at X-Force (82369), Tenable (68903), SecurityFocus (BID 59000†), OSVDB (90630†) and Secunia (SA52277†). Similar entries are available at VDB-7759, VDB-7836, VDB-68665 and VDB-64455. Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Name

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.1

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

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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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: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 68903
Nessus Name: Ubuntu 10.04 LTS / 12.04 LTS / 12.10 / 13.04 : libxml2 vulnerabilities (USN-1904-1)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Port: 🔍

OpenVAS ID: 892652
OpenVAS Name: Debian Security Advisory DSA 2652-1 (libxml2 - external entity expansion
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: git.gnome.org

Timelineinfo

12/06/2012 🔍
02/19/2013 +75 days 🔍
02/19/2013 +0 days 🔍
02/20/2013 +1 days 🔍
02/26/2013 +6 days 🔍
02/26/2013 +0 days 🔍
02/28/2013 +2 days 🔍
07/16/2013 +138 days 🔍
08/11/2013 +26 days 🔍
01/21/2014 +163 days 🔍
05/05/2021 +2661 days 🔍

Sourcesinfo

Advisory: CVEs for libxml2 and expat internal and external XML entity expansion
Researcher: Kurt Seifried
Organization: Red Hat
Status: Confirmed
Coordinated: 🔍

CVE: CVE-2013-0339 (🔍)
GCVE (CVE): GCVE-0-2013-0339
GCVE (VulDB): GCVE-100-7835

OVAL: 🔍

X-Force: 82369
SecurityFocus: 59000
Secunia: 52277 - Libxml2 Entity Expansion Denial of Service Vulnerability, Less Critical
OSVDB: 90630
SecurityTracker: 1028212 - Libxml2 Entity Expansion May Let Remote Users Deny Service
Vulnerability Center: 40959 - libxml2 Entities Expansion Error Allows Remote DoS via a Crafted XML File, Medium

See also: 🔍

Entryinfo

Created: 02/28/2013 10:37
Updated: 05/05/2021 15:08
Changes: 02/28/2013 10:37 (87), 05/08/2017 09:00 (4), 05/05/2021 15:08 (3)
Complete: 🔍
Cache ID: 216::103

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