strongSwan up to 5.0.4 XAuth/EAP asn1.c is_asn1 XAuth Username/EAP Identity memory corruption

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.
5.3$0-$5k0.00

A vulnerability classified as problematic has been found in strongSwan up to 5.0.4 (Network Encryption Software). Affected is the function is_asn1 in the library libstrongswan/asn1/asn1.c of the component XAuth/EAP Handler. The manipulation as part of a XAuth Username/EAP Identity leads to a memory corruption vulnerability. CWE is classifying the issue as CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer. This is going to have an impact on availability. CVE summarizes:

The is_asn1 function in strongSwan 4.1.11 through 5.0.4 does not properly validate the return value of the asn1_length function, which allows remote attackers to cause a denial of service (segmentation fault) via a (1) XAuth username, (2) EAP identity, or (3) PEM encoded file that starts with a 0x04, 0x30, or 0x31 character followed by an ASN.1 length value that triggers an integer overflow.

The weakness was presented 07/29/2013 by Ewan Smythe as strongSwan Denial-of-Service Vulnerability (CVE-2013-5018) as confirmed blog post (Website). The advisory is shared for download at strongswan.org. This vulnerability is traded as CVE-2013-5018 since 07/30/2013. The exploitability is told to be difficult. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Technical details and a public exploit are known.

After 3 days, there has been an exploit disclosed. It is declared as proof-of-concept. The vulnerability scanner Nessus provides a plugin with the ID 75115 (openSUSE Security Update : strongswan (openSUSE-SU-2013:1332-1)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family SuSE Local Security Checks. The commercial vulnerability scanner Qualys is able to test this issue with plugin 166641 (SUSE Enterprise Linux Security Update for Strongswan (SUSE-SU-2013:1866-1)).

Upgrading to version 5.1.0 eliminates this vulnerability. The upgrade is hosted for download at strongswan.org. Applying the patch 4.1.11-4.2.17_is_asn1.patch/4.3.0-5.0.4_is_asn1.patch is able to eliminate this problem. The bugfix is ready for download at download.strongswan.org. The best possible mitigation is suggested to be upgrading to the latest version. A possible mitigation has been published 3 days after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at X-Force (86125) and Tenable (75115). See 11069 for similar entry.

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB CVSS-B Score: 🔍
VulDB CVSS-BT Score: 🔍
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.9
VulDB Meta Temp Score: 5.3

VulDB Base Score: 5.9
VulDB Temp Score: 5.3
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
unlockunlockunlockunlockunlockunlock
unlockunlockunlockunlockunlockunlock
unlockunlockunlockunlockunlockunlock

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

NVD Base Score: 🔍

Exploitinginfo

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

Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Dayunlockunlockunlockunlock
Todayunlockunlockunlockunlock

Nessus ID: 75115
Nessus Name: openSUSE Security Update : strongswan (openSUSE-SU-2013:1332-1)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Port: 🔍

OpenVAS ID: 866838
OpenVAS Name: Fedora Update for strongswan FEDORA-2013-14481
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

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

Upgrade: strongSwan 5.1.0
Patch: 4.1.11-4.2.17_is_asn1.patch/4.3.0-5.0.4_is_asn1.patch

Timelineinfo

07/29/2013 🔍
07/30/2013 +1 days 🔍
08/01/2013 +2 days 🔍
08/01/2013 +0 days 🔍
08/01/2013 +0 days 🔍
08/01/2013 +0 days 🔍
08/01/2013 +0 days 🔍
08/05/2013 +4 days 🔍
08/26/2013 +21 days 🔍
08/28/2013 +2 days 🔍
06/13/2014 +289 days 🔍
05/21/2021 +2534 days 🔍

Sourcesinfo

Advisory: strongSwan Denial-of-Service Vulnerability (CVE-2013-5018)
Researcher: Ewan Smythe
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2013-5018 (🔍)
OVAL: 🔍

X-Force: 86125
Vulnerability Center: 41210 - strongSwan Before 5.1.0 Remote Denial of Service via Crafted Xauth Usernames, EAP Identities or PEM Encoded Files, High
SecurityFocus: 61564 - strongSwan 'is_asn1()' Function Denial of Service Vulnerability
Secunia: 54315 - strongSwan "is_asn1()" XAuth Username and EAP Identity Handling Denial of Servic, Moderately Critical
OSVDB: 95904

See also: 🔍

Entryinfo

Created: 08/05/2013 14:36
Updated: 05/21/2021 08:19
Changes: 08/05/2013 14:36 (85), 08/21/2017 08:44 (10), 05/21/2021 08:19 (3)
Complete: 🔍

Discussion

No comments yet. Languages: en.

Please log in to comment.

Interested in the pricing of exploits?

See the underground prices here!