libssh up to 0.8.8/0.9.3 AES-CTR/DES resource consumption

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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.
6.0	$0-$5k	0.00

Summaryinfo

A vulnerability marked as problematic has been reported in libssh up to 0.8.8/0.9.3. This affects an unknown function of the component AES-CTR/DES. This manipulation causes resource consumption. This vulnerability appears as CVE-2020-1730. The attack may be initiated remotely. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic was found in libssh up to 0.8.8/0.9.3. Affected by this vulnerability is an unknown code of the component AES-CTR/DES. The manipulation with an unknown input leads to a resource consumption vulnerability. The CWE definition for the vulnerability is CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. As an impact it is known to affect availability. The summary by CVE is:

A flaw was found in libssh versions before 0.8.9 and before 0.9.4 in the way it handled AES-CTR (or DES ciphers if enabled) ciphers. The server or client could crash when the connection hasn't been fully initialized and the system tries to cleanup the ciphers when closing the connection. The biggest threat from this vulnerability is system availability.

The weakness was presented 04/13/2020 as not defined bug report (Bugzilla). The advisory is shared at bugzilla.redhat.com. This vulnerability is known as CVE-2020-1730 since 11/27/2019. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 236741 (Alibaba Cloud Linux 3 : 0067: libssh (ALINUX3-SA-2022:0067)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 0.8.9 or 0.9.4 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (236741). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Name

libssh

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.0
VulDB Meta Temp Score: 6.0

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

NVD Base Score: 7.5
NVD Vector: 🔍

CNA Base Score: 5.3
CNA Vector (Red Hat, Inc.): 🔍

CVSSv2info

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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Resource consumption
CWE: CWE-400 / 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-Day	Unlock	Unlock	Unlock	Unlock
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Nessus ID: 236741
Nessus Name: Alibaba Cloud Linux 3 : 0067: libssh (ALINUX3-SA-2022:0067)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: libssh 0.8.9/0.9.4

Timelineinfo

11/27/2019 🔍
04/13/2020 +138 days 🔍
04/14/2020 +1 days 🔍
05/16/2025 +1858 days 🔍

Sourcesinfo

Advisory: USN-4327-1
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2020-1730 (🔍)
GCVE (CVE): GCVE-0-2020-1730
GCVE (VulDB): GCVE-100-153073

Entryinfo

Created: 04/14/2020 09:05
Updated: 05/16/2025 04:01
Changes: 04/14/2020 09:05 (39), 04/14/2020 09:10 (17), 10/09/2020 14:49 (1), 05/18/2024 15:11 (18), 05/18/2024 15:17 (12), 05/16/2025 04:01 (5)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.