Tor up to 0.2.4.19 Relay/Hidden Service Identity Key Generator cryptographic issues

EntryHistoryDiffjsonxmlCTI

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.
3.2	$0-$5k	0.00

A vulnerability classified as problematic was found in Tor (Network Encryption Software). This vulnerability affects an unknown code block of the component Relay/Hidden Service Identity Key Generator. The manipulation with an unknown input leads to a cryptographic issues vulnerability. The CWE definition for the vulnerability is CWE-310. As an impact it is known to affect integrity. CVE summarizes:

Tor before 0.2.4.20, when OpenSSL 1.x is used in conjunction with a certain HardwareAccel setting on Intel Sandy Bridge and Ivy Bridge platforms, does not properly generate random numbers for (1) relay identity keys and (2) hidden-service identity keys, which might make it easier for remote attackers to bypass cryptographic protection mechanisms via unspecified vectors.

The weakness was shared 12/23/2013 as [tor-talk] Tor 0.2.4.20 is released as confirmed posting (Website). The advisory is available at lists.torproject.org. This vulnerability was named CVE-2013-7295 since 01/17/2014. The exploitation appears to be difficult. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1600 by the MITRE ATT&CK project. The advisory points out:

Do not allow OpenSSL engines to replace the PRNG, even when HardwareAccel is set. The only default builtin PRNG engine uses the Intel RDRAND instruction to replace the entire PRNG, and ignores all attempts to seed it with more entropy.

The vulnerability scanner Nessus provides a plugin with the ID 75409 (openSUSE Security Update : tor (openSUSE-SU-2014:0143-1)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family SuSE Local Security Checks.

Upgrading to version 0.2.4.20 eliminates this vulnerability. A possible mitigation has been published immediately after the disclosure of the vulnerability. The posting contains the following remark:

(...) the right response to a new alleged entropy source is never to discard all previously used entropy sources.

The vulnerability is also documented in the databases at X-Force (90506) and Tenable (75409).

Productinfo

Type

Network Encryption Software

Name

Version

License

open-source

CPE 2.3info

CPE 2.2info

CVSSv4info

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

CVSSv3info

VulDB Meta Base Score: 3.7
VulDB Meta Temp Score: 3.2

VulDB Base Score: 3.7
VulDB Temp Score: 3.2
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

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VulDB Base Score: 🔍
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Exploitinginfo

Class: Cryptographic issues
CWE: CWE-310
CAPEC: 🔍
ATT&CK: 🔍

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: 75409
Nessus Name: openSUSE Security Update : tor (openSUSE-SU-2014:0143-1)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Port: 🔍

Threat Intelligenceinfo

Interest: 🔍
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Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍

Upgrade: Tor 0.2.4.20

Timelineinfo

12/23/2013 🔍
12/23/2013 +0 days 🔍
12/23/2013 +0 days 🔍
12/23/2013 +0 days 🔍
12/31/2013 +8 days 🔍
01/17/2014 +17 days 🔍
01/17/2014 +0 days 🔍
02/06/2014 +20 days 🔍
06/13/2014 +127 days 🔍
06/04/2021 +2548 days 🔍

Sourcesinfo

Advisory: [tor-talk] Tor 0.2.4.20 is released
Status: Confirmed

CVE: CVE-2013-7295 (🔍)
X-Force: 90506 - Tor keys weak security, Low Risk
Vulnerability Center: 43180 - Tor Before 0.2.4.20 Remote Security Bypass Vulnerability via Unspecified Vectors, Medium
SecurityFocus: 64651 - Tor Random Number Generation Weakness
OSVDB: 101527

Entryinfo

Created: 12/31/2013 12:27
Updated: 06/04/2021 17:30
Changes: 12/31/2013 12:27 (73), 05/20/2017 10:29 (3), 06/04/2021 17:30 (3)
Complete: 🔍