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.
8.4	$0-$5k	0.00

A vulnerability, which was classified as critical, has been found in OpenSMTPD up to 5.7.1. This issue affects the function req_ca_vrfy_smtp/req_ca_vrfy_mta of the file /etc/master.passwd. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Use-after-free vulnerability in OpenSMTPD before 5.7.2 allows remote attackers to cause a denial of service (crash) or execute arbitrary code via vectors involving req_ca_vrfy_smtp and req_ca_vrfy_mta.

The bug was discovered 10/02/2015. The weakness was presented 10/16/2017 with Qualys (oss-sec). It is possible to read the advisory at openwall.com. The identification of this vulnerability is CVE-2015-7687 since 10/03/2015. The exploitation is known to be easy. 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 vulnerability was handled as a non-public zero-day exploit for at least 29 days. During that time the estimated underground price was around $0-$5k. The vulnerability scanner Nessus provides a plugin with the ID 89451 (Fedora 23 : opensmtpd-5.7.3p1-1.fc23 (2015-ed1c673f09)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Fedora Local Security Checks and running in the context l.

Upgrading to version 5.7.2 eliminates this vulnerability. A possible mitigation has been published even before and not after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (89451).

Productinfo

Name

• OpenSMTPD

Version

• 5.7.0
• 5.7.1

CPE 2.3info

• 🔍
• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍
• 🔍

CVSSv4info

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

CVSSv3info

VulDB Meta Base Score: 8.5
VulDB Meta Temp Score: 8.4

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 9.8
NVD Vector: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
unlock	unlock	unlock	unlock	unlock	unlock
unlock	unlock	unlock	unlock	unlock	unlock
unlock	unlock	unlock	unlock	unlock	unlock

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

NVD Base Score: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	unlock	unlock	unlock	unlock
Today	unlock	unlock	unlock	unlock

Nessus ID: 89451
Nessus Name: Fedora 23 : opensmtpd-5.7.3p1-1.fc23 (2015-ed1c673f09)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: OpenSMTPD 5.7.2

Timelineinfo

10/02/2015 🔍
10/02/2015 +0 days 🔍
10/03/2015 +1 days 🔍
10/31/2015 +28 days 🔍
03/04/2016 +125 days 🔍
10/16/2017 +591 days 🔍
10/16/2017 +0 days 🔍
10/17/2017 +1 days 🔍
01/03/2023 +1904 days 🔍

Sourcesinfo

Advisory: FEDORA-2015-ed1c673f09
Researcher: Qualys
Organization: Qualys
Status: Not defined
Confirmation: 🔍

CVE: CVE-2015-7687 (🔍)
SecurityFocus: 76975 - OpenSMTPD CVE-2015-7687 Use After Free Remote Code Execution Vulnerability

Entryinfo

Created: 10/17/2017 09:04
Updated: 01/03/2023 17:11
Changes: 10/17/2017 09:04 (71), 05/26/2020 20:49 (2), 01/17/2021 08:45 (2), 01/03/2023 17:11 (3)
Complete: 🔍

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