OpenVPN ssl_verify_openssl.c ASN1_STRING_to_UTF8 double free

CVSS Meta Temp Score
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CTI Interest Score
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5.5$0-$5k0.00

Summaryinfo

A vulnerability was found in OpenVPN and classified as critical. Affected by this issue is the function ASN1_STRING_to_UTF8 of the file ssl_verify_openssl.c. The manipulation results in double free. This vulnerability was named CVE-2017-7521. The attack may be performed from remote. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in OpenVPN (Network Encryption Software) (the affected version is unknown). Affected is the function ASN1_STRING_to_UTF8 of the file ssl_verify_openssl.c. The manipulation with an unknown input leads to a double free vulnerability. CWE is classifying the issue as CWE-415. The product calls free() twice on the same memory address, potentially leading to modification of unexpected memory locations. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

OpenVPN versions before 2.4.3 and before 2.3.17 are vulnerable to remote denial-of-service due to memory exhaustion caused by memory leaks and double-free issue in extract_x509_extension().

The bug was discovered 06/22/2017. The weakness was presented 06/21/2017 by Guido Vranken with https://guidovranken.wordpress.com as The OpenVPN post-audit bug bonanza as not defined blog post (Website). The advisory is shared for download at guidovranken.wordpress.com. This vulnerability is traded as CVE-2017-7521 since 04/05/2017. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 100964 (Slackware 13.0 / 13.1 / 13.37 / 14.0 / 14.1 / 14.2 / current : openvpn (SSA:2017-172-01)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Slackware Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 196832 (Ubuntu Security Notification for Openvpn Vulnerabilities (USN-3339-1)).

Upgrading eliminates this vulnerability. The upgrade is hosted for download at openvpn.net. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Tenable (100964) and SecurityFocus (BID 99230†). See VDB-102707, VDB-102709, VDB-102710 and VDB-102711 for similar entries. Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Name

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.7
VulDB Meta Temp Score: 5.6

VulDB Base Score: 5.6
VulDB Temp Score: 5.4
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 5.9
NVD Vector: 🔍

CVSSv2info

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

NVD Base Score: 🔍

Exploitinginfo

Class: Double free
CWE: CWE-415 / CWE-119
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: 100964
Nessus Name: Slackware 13.0 / 13.1 / 13.37 / 14.0 / 14.1 / 14.2 / current : openvpn (SSA:2017-172-01)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 867773
OpenVAS Name: Fedora Update for openvpn FEDORA-2017-5596f2f94d
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: 🔍

Upgrade: openvpn.net

Timelineinfo

04/05/2017 🔍
06/21/2017 +77 days 🔍
06/21/2017 +0 days 🔍
06/21/2017 +0 days 🔍
06/22/2017 +1 days 🔍
06/22/2017 +0 days 🔍
06/22/2017 +0 days 🔍
06/27/2017 +4 days 🔍
12/29/2020 +1281 days 🔍

Sourcesinfo

Advisory: The OpenVPN post-audit bug bonanza
Researcher: Guido Vranken
Organization: https://guidovranken.wordpress.com
Status: Not defined
Confirmation: 🔍

CVE: CVE-2017-7521 (🔍)
GCVE (CVE): GCVE-0-2017-7521
GCVE (VulDB): GCVE-100-102708

OVAL: 🔍

SecurityFocus: 99230 - OpenVPN Multiple Security Vulnerabilities
SecurityTracker: 1038768

See also: 🔍

Entryinfo

Created: 06/21/2017 17:48
Updated: 12/29/2020 11:04
Changes: 06/21/2017 17:48 (78), 10/19/2019 12:53 (6), 12/29/2020 11:04 (2)
Complete: 🔍
Cache ID: 216::103

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