Tor up to 0.3.1.8 PEM Hang memory corruption

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6.1	$0-$5k	0.00

Summaryinfo

A vulnerability described as problematic has been identified in Tor up to 0.2.5.15/0.2.8.16/0.2.9.13/0.3.0.12/0.3.1.8. Affected is an unknown function of the component PEM Handler. Executing a manipulation can lead to memory corruption (Hang). The identification of this vulnerability is CVE-2017-8821. The attack may be launched remotely. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability has been found in Tor up to 0.2.5.15/0.2.8.16/0.2.9.13/0.3.0.12/0.3.1.8 (Network Encryption Software) and classified as problematic. This vulnerability affects an unknown code block of the component PEM Handler. The manipulation with an unknown input leads to a memory corruption vulnerability (Hang). The CWE definition for the vulnerability is CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer. As an impact it is known to affect availability. CVE summarizes:

In Tor before 0.2.5.16, 0.2.6 through 0.2.8 before 0.2.8.17, 0.2.9 before 0.2.9.14, 0.3.0 before 0.3.0.13, and 0.3.1 before 0.3.1.9, an attacker can cause a denial of service (application hang) via crafted PEM input that signifies a public key requiring a password, which triggers an attempt by the OpenSSL library to ask the user for the password, aka TROVE-2017-011.

The bug was discovered 12/01/2017. The weakness was shared 12/01/2017 as TROVE-2017-011 as confirmed blog post (Website). The advisory is shared for download at blog.torproject.org. The blog post contains:

There are new stable releases today, fixing the following security issues.

This vulnerability was named CVE-2017-8821 since 05/07/2017. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are neither technical details nor an exploit publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 104975 (Debian DSA-4054-1 : tor - security update), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Debian Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 176234 (Debian Security Update for tor (DSA 4054-1)).

Upgrading to version 0.2.5.16, 0.2.8.17, 0.2.8.14, 0.3.0.13 or 0.3.1.9 eliminates this vulnerability. A possible mitigation has been published immediately after the disclosure of the vulnerability. The blog post contains the following remark:

Tor 0.3.1.9 backports important security and stability fixes from the 0.3.2 development series. All Tor users should upgrade to this release, or to another of the releases coming out today.

The vulnerability is also documented in the vulnerability database at Tenable (104975). The entries VDB-110162, VDB-110163, VDB-110165 and VDB-110166 are related to this item. Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• Network Encryption Software

Name

• Tor

Version

• 0.2.5.0
• 0.2.5.1
• 0.2.5.2
• 0.2.5.3
• 0.2.5.4
• 0.2.5.5
• 0.2.5.6
• 0.2.5.7
• 0.2.5.8
• 0.2.5.9
• 0.2.5.10
• 0.2.5.11
• 0.2.5.12
• 0.2.5.13
• 0.2.5.14
• 0.2.5.15
• 0.2.8.0
• 0.2.8.1
• 0.2.8.2
• 0.2.8.3
• 0.2.8.4
• 0.2.8.5
• 0.2.8.6
• 0.2.8.7
• 0.2.8.8
• 0.2.8.9
• 0.2.8.10
• 0.2.8.11
• 0.2.8.12
• 0.2.8.13
• 0.2.8.14
• 0.2.8.15
• 0.2.8.16
• 0.2.9.0
• 0.2.9.1
• 0.2.9.2
• 0.2.9.3
• 0.2.9.4
• 0.2.9.5
• 0.2.9.6
• 0.2.9.7
• 0.2.9.8
• 0.2.9.9
• 0.2.9.10
• 0.2.9.11
• 0.2.9.12
• 0.2.9.13
• 0.3.0.0
• 0.3.0.1
• 0.3.0.2
• 0.3.0.3
• 0.3.0.4
• 0.3.0.5
• 0.3.0.6
• 0.3.0.7
• 0.3.0.8
• 0.3.0.9
• 0.3.0.10
• 0.3.0.11
• 0.3.0.12
• 0.3.1.0
• 0.3.1.1
• 0.3.1.2
• 0.3.1.3
• 0.3.1.4
• 0.3.1.5
• 0.3.1.6
• 0.3.1.7
• 0.3.1.8

License

• open-source

CPE 2.3info

• 🔍
• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍
• 🔍

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.3

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.5
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

Name: Hang
Class: Memory corruption / Hang
CWE: CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
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: 104975
Nessus Name: Debian DSA-4054-1 : tor - security update
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 703791
OpenVAS Name: Debian Security Advisory DSA 4054-1 (tor - security update)
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: Tor 0.2.5.16/0.2.8.17/0.2.8.14/0.3.0.13/0.3.1.9

Timelineinfo

05/07/2017 🔍
12/01/2017 +208 days 🔍
12/01/2017 +0 days 🔍
12/01/2017 +0 days 🔍
12/03/2017 +2 days 🔍
12/03/2017 +0 days 🔍
12/04/2017 +1 days 🔍
12/11/2019 +737 days 🔍

Sourcesinfo

Advisory: TROVE-2017-011
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2017-8821 (🔍)
GCVE (CVE): GCVE-0-2017-8821
GCVE (VulDB): GCVE-100-110164

OVAL: 🔍
See also: 🔍

Entryinfo

Created: 12/03/2017 15:04
Updated: 12/11/2019 21:33
Changes: 12/03/2017 15:04 (78), 12/11/2019 21:33 (2)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

Discussion

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