Mattermost Server up to 5.15.x Backtick Markdown denial of service

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.
6.1$0-$5k0.00

Summaryinfo

A vulnerability was found in Mattermost Server up to 5.15.x. It has been classified as problematic. The affected element is an unknown function of the component Backtick Handler. Performing a manipulation as part of Markdown results in denial of service. This vulnerability is reported as CVE-2019-20857. The attack is possible to be carried out remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as problematic has been found in Mattermost Server up to 5.15.x. This affects an unknown code block of the component Backtick Handler. The manipulation as part of a Markdown leads to a denial of service vulnerability. CWE is classifying the issue as CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. This is going to have an impact on availability. The summary by CVE is:

An issue was discovered in Mattermost Server before 5.16.0. It allows attackers to cause a denial of service (markdown renderer hang) via many backtick characters.

The weakness was disclosed 06/19/2020 (Website). It is possible to read the advisory at mattermost.com. This vulnerability is uniquely identified as CVE-2019-20857 since 06/19/2020. The exploitability is told to be easy. 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 attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

Upgrading to version 5.16.0 eliminates this vulnerability.

The entries VDB-156956, VDB-156957, VDB-156958 and VDB-156959 are pretty similar. 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
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

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

NVD Base Score: 🔍

Exploitinginfo

Class: Denial of service
CWE: CWE-404
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: Mattermost Server 5.16.0

Timelineinfo

06/19/2020 🔍
06/19/2020 +0 days 🔍
06/19/2020 +0 days 🔍
10/25/2020 +128 days 🔍

Sourcesinfo

Advisory: mattermost.com
Status: Not defined
Confirmation: 🔍

CVE: CVE-2019-20857 (🔍)
GCVE (CVE): GCVE-0-2019-20857
GCVE (VulDB): GCVE-100-156987
See also: 🔍

Entryinfo

Created: 06/19/2020 22:24
Updated: 10/25/2020 16:44
Changes: 06/19/2020 22:24 (40), 06/19/2020 22:29 (17), 10/25/2020 16:44 (1)
Complete: 🔍
Cache ID: 216::103

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

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Interested in the pricing of exploits?

See the underground prices here!