Squid Proxy up to 3.2.13/3.3.13/3.4.12/3.5.3 SSL-Bump Certificate Validator input validation

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.
5.7	$0-$5k	0.00

Summaryinfo

A vulnerability classified as critical was found in Squid Proxy up to 3.2.13/3.3.13/3.4.12/3.5.3. The affected element is an unknown function of the component SSL-Bump Certificate Validator. The manipulation results in input validation. This vulnerability is known as CVE-2015-3455. No exploit is available. It is advisable to implement a patch to correct this issue.

Detailsinfo

A vulnerability, which was classified as critical, was found in Squid Proxy up to 3.2.13/3.3.13/3.4.12/3.5.3 (Firewall Software). Affected is an unknown function of the component SSL-Bump Certificate Validator. The manipulation with an unknown input leads to a input validation vulnerability. CWE is classifying the issue as CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. This is going to have an impact on confidentiality, and integrity.

The weakness was published 05/01/2015 as SQUID-2015:1 as confirmed advisory (Website). The advisory is shared for download at squid-cache.org. This vulnerability is traded as CVE-2015-3455 since 04/29/2015. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are neither technical details nor an exploit publicly available. The advisory points out:

The bug is important because it allows remote servers to bypass client certificate validation. Some attackers may also be able to use valid certificates for one domain signed by a global Certificate Authority to abuse an unrelated domain.

The vulnerability was handled as a non-public zero-day exploit for at least 2 days. During that time the estimated underground price was around $5k-$25k. The vulnerability scanner Nessus provides a plugin with the ID 83276 (Mandriva Linux Security Advisory : squid (MDVSA-2015:230)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Mandriva Local Security Checks. The commercial vulnerability scanner Qualys is able to test this issue with plugin 276088 (Fedora Security Update for squid (FEDORA-2016-7b40eb9e29)). The advisory illustrates:

However, the bug is exploitable only if you have configured Squid to perform SSL Bumping with the "client-first" or "bump" mode of operation.

Applying a patch is able to eliminate this problem. A possible mitigation has been published immediately after the disclosure of the vulnerability. The advisory contains the following remark:

Sites that do not use SSL-Bump are not vulnerable.

Furthermore it is possible to detect and prevent this kind of attack with TippingPoint and the filter 22091.

The vulnerability is also documented in the databases at X-Force (102789), Tenable (83276), SecurityFocus (BID 74438†), SecurityTracker (ID 1032221†) and Vulnerability Center (SBV-50733†). Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• Firewall Software

Vendor

• Squid

Name

• Proxy

Version

• 3.2.0
• 3.2.1
• 3.2.2
• 3.2.3
• 3.2.4
• 3.2.5
• 3.2.6
• 3.2.7
• 3.2.8
• 3.2.9
• 3.2.10
• 3.2.11
• 3.2.12
• 3.2.13
• 3.3.0
• 3.3.1
• 3.3.2
• 3.3.3
• 3.3.4
• 3.3.5
• 3.3.6
• 3.3.7
• 3.3.8
• 3.3.9
• 3.3.10
• 3.3.11
• 3.3.12
• 3.3.13
• 3.4.0
• 3.4.1
• 3.4.2
• 3.4.3
• 3.4.4
• 3.4.5
• 3.4.6
• 3.4.7
• 3.4.8
• 3.4.9
• 3.4.10
• 3.4.11
• 3.4.12
• 3.5.0
• 3.5.1
• 3.5.2
• 3.5.3

License

• open-source

Website

• Vendor: http://www.squid-cache.org/

CPE 2.3info

• 🔍
• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍
• 🔍

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.5
VulDB Meta Temp Score: 5.7

VulDB Base Score: 6.5
VulDB Temp Score: 5.7
VulDB Vector: 🔍
VulDB Reliability: 🔍

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: Input validation
CWE: CWE-20
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Unproven

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 83276
Nessus Name: Mandriva Linux Security Advisory : squid (MDVSA-2015:230)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Port: 🔍

OpenVAS ID: 103320
OpenVAS Name: Squid SSL-Bump Certificate Validation Bypass Vulnerability
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Patch
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍
TippingPoint: 🔍
Fortigate IPS: 🔍

Timelineinfo

04/29/2015 🔍
04/29/2015 +0 days 🔍
05/01/2015 +2 days 🔍
05/01/2015 +0 days 🔍
05/01/2015 +0 days 🔍
05/02/2015 +1 days 🔍
05/02/2015 +0 days 🔍
05/02/2015 +0 days 🔍
05/07/2015 +5 days 🔍
05/18/2015 +11 days 🔍
06/28/2015 +41 days 🔍
05/10/2022 +2508 days 🔍

Sourcesinfo

Vendor: squid-cache.org

Advisory: SQUID-2015:1
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2015-3455 (🔍)
GCVE (CVE): GCVE-0-2015-3455
GCVE (VulDB): GCVE-100-75180
X-Force: 102789 - Squid X509 security bypass
SecurityFocus: 74438 - SQUID CVE-2015-3455 SSL Certificate Validation Security Bypass Vulnerability
SecurityTracker: 1032221 - Squid SSL-Bump Certificate Validation Flaw Lets Remote Servers Bypass Client-side Certificate Validation
Vulnerability Center: 50733 - Squid 3.2, 3.3, 3.4, 3.5 Remote SSL Servers Spoofing via Valid Certificates, Low

Entryinfo

Created: 05/02/2015 18:52
Updated: 05/10/2022 08:55
Changes: 05/02/2015 18:52 (85), 07/01/2017 20:00 (5), 05/10/2022 08:51 (3), 05/10/2022 08:55 (1)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

Discussion

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