stunnel up to 4.54 NTLM Authentication code injection

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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A vulnerability was found in stunnel and classified as critical. Affected by this issue is an unknown code block of the component NTLM Authentication. The manipulation with an unknown input leads to a code injection vulnerability. Using CWE to declare the problem leads to CWE-94. The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. Impacted is confidentiality, integrity, and availability. CVE summarizes:

stunnel 4.21 through 4.54, when CONNECT protocol negotiation and NTLM authentication are enabled, does not correctly perform integer conversion, which allows remote proxy servers to execute arbitrary code via a crafted request that triggers a buffer overflow.

The weakness was presented 03/08/2013 by Wolfgang Ettlingers (Website). The advisory is available at This vulnerability is handled as CVE-2013-1762 since 02/19/2013. The exploitation is known to be difficult. The attack may be launched remotely. No form of authentication is required for exploitation. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1059 by the MITRE ATT&CK project.

The vulnerability scanner Nessus provides a plugin with the ID 68803 (Oracle Linux 6 : stunnel (ELSA-2013-0714)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Oracle Linux Local Security Checks.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the databases at X-Force (82522) and Tenable (68803). See 7598 for similar entry.




CPE 2.3info

CPE 2.2info


VulDB Meta Base Score: 8.6
VulDB Meta Temp Score: 8.6

VulDB Base Score: 8.6
VulDB Temp Score: 8.6
VulDB Vector: 🔍
VulDB Reliability: 🔍



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Class: Code injection
CWE: CWE-94 / CWE-74 / CWE-707
ATT&CK: T1059

Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

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EPSS Percentile: 🔍

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Current Price Estimation: 🔍


Nessus ID: 68803
Nessus Name: Oracle Linux 6 : stunnel (ELSA-2013-0714)
Nessus File: 🔍
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OpenVAS ID: 892664
OpenVAS Name: Debian Security Advisory DSA 2664-1 (stunnel4 - buffer overflow
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Threat Intelligenceinfo

Interest: 🔍
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Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔍


02/05/2013 🔍
02/19/2013 +14 days 🔍
03/03/2013 +12 days 🔍
03/08/2013 +5 days 🔍
03/08/2013 +0 days 🔍
03/25/2013 +17 days 🔍
07/12/2013 +109 days 🔍
03/24/2015 +620 days 🔍
12/30/2021 +2472 days 🔍


Advisory: RHSA-2013:0714
Researcher: Wolfgang Ettlingers
Status: Not defined
Confirmation: 🔍

CVE: CVE-2013-1762 (🔍)

X-Force: 82522
Vulnerability Center: 38893 - stunnel Improper Integer Conversion Allows Remote Code Execution via a Crafted Request, High
SecurityFocus: 57755 - OpenSSL CVE-2012-2686 Remote Denial of Service Vulnerability

See also: 🔍


Created: 03/24/2015 12:22 PM
Updated: 12/30/2021 12:48 AM
Changes: 03/24/2015 12:22 PM (67), 04/26/2017 05:44 PM (6), 12/30/2021 12:24 AM (3), 12/30/2021 12:34 AM (1), 12/30/2021 12:48 AM (2)
Complete: 🔍


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