OpenVPN asn1_buf_to_c_string null pointer dereference

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.
5.1$0-$5k0.00

Summaryinfo

A vulnerability marked as problematic has been reported in OpenVPN. This affects the function asn1_buf_to_c_string. This manipulation causes null pointer dereference. This vulnerability is registered as CVE-2017-7522. Remote exploitation of the attack is possible. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in OpenVPN (Network Encryption Software) (the affected version is unknown). It has been declared as problematic. Affected by this vulnerability is the function asn1_buf_to_c_string. The manipulation with an unknown input leads to a null pointer dereference vulnerability. The CWE definition for the vulnerability is CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. As an impact it is known to affect availability. The summary by CVE is:

OpenVPN versions before 2.4.3 and before 2.3.17 are vulnerable to denial-of-service by authenticated remote attacker via sending a certificate with an embedded NULL character.

The bug was discovered 06/22/2017. The weakness was published 06/21/2017 by Guido Vranken with https://guidovranken.wordpress.com as The OpenVPN post-audit bug bonanza as not defined blog post (Website). It is possible to read the advisory at guidovranken.wordpress.com. This vulnerability is known as CVE-2017-7522 since 04/05/2017. The attack can be launched remotely. A single authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit. Responsible for the vulnerability is the following code: 

for (i = 0; i < orig->len; ++i)
{
    if (orig->p[i] == '\0')
    {
        return "ERROR: embedded null value";
    }
}

The vulnerability scanner Nessus provides a plugin with the ID 101064 (Amazon Linux AMI : openvpn (ALAS-2017-852)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Amazon Linux Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 276727 (Fedora Security Update for openvpn (FEDORA-2017-5596f2f94d)).

Upgrading eliminates this vulnerability. The upgrade is hosted for download at openvpn.net. A possible mitigation has been published 6 days after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Tenable (101064) and SecurityFocus (BID 99230†). Similar entries are available at VDB-102707, VDB-102708, VDB-102709 and VDB-102710. 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: 5.4
VulDB Meta Temp Score: 5.3

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 6.5
NVD Vector: 🔍

CVSSv2info

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

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

NVD Base Score: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Nessus ID: 101064
Nessus Name: Amazon Linux AMI : openvpn (ALAS-2017-852)
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 🔍
06/22/2017 +1 days 🔍
06/22/2017 +0 days 🔍
06/27/2017 +5 days 🔍
06/27/2017 +0 days 🔍
06/28/2017 +1 days 🔍
12/29/2020 +1280 days 🔍

Sourcesinfo

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

CVE: CVE-2017-7522 (🔍)
GCVE (CVE): GCVE-0-2017-7522
GCVE (VulDB): GCVE-100-102715
SecurityFocus: 99230 - OpenVPN Multiple Security Vulnerabilities
SecurityTracker: 1038768

See also: 🔍

Entryinfo

Created: 06/21/2017 17:48
Updated: 12/29/2020 11:39
Changes: 06/21/2017 17:48 (79), 10/19/2019 14:39 (6), 12/29/2020 11:39 (3)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Do you need the next level of professionalism?

Upgrade your account now!