Tor up to 0.3.1.8 null pointer dereference

CVSS Meta Temp Score
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CTI Interest Score
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6.1$0-$5k0.00

Summaryinfo

A vulnerability marked as problematic has been reported in Tor up to 0.2.5.15/0.2.8.16/0.2.9.13/0.3.0.12/0.3.1.8. This impacts an unknown function. Performing a manipulation results in null pointer dereference. This vulnerability was named CVE-2017-8820. The attack may be initiated remotely. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, was 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). This affects an unknown code. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. The summary by CVE is:

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, remote attackers can cause a denial of service (NULL pointer dereference and application crash) against directory authorities via a malformed descriptor, aka TROVE-2017-010.

The bug was discovered 12/01/2017. The weakness was presented 12/01/2017 as TROVE-2017-010 as confirmed blog post (Website). It is possible to read the advisory at blog.torproject.org. The blog post contains:

There are new stable releases today, fixing the following security issues.
This vulnerability is uniquely identified as CVE-2017-8820 since 05/07/2017. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not 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). See VDB-110162, VDB-110164, VDB-110165 and VDB-110166 for similar entries. Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Name

Version

License

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

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

NVD Base Score: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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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-2017-010
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2017-8820 (🔍)
GCVE (CVE): GCVE-0-2017-8820
GCVE (VulDB): GCVE-100-110163

OVAL: 🔍
See also: 🔍

Entryinfo

Created: 12/03/2017 15:04
Updated: 12/11/2019 21:19
Changes: 12/03/2017 15:04 (76), 12/11/2019 21:19 (2)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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