cloud-init up to 19.4 Mersenne Twister cloudinit/util.py rand_str PRNG random values

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.
5.3$0-$5k0.00

Summaryinfo

A vulnerability described as critical has been identified in cloud-init up to 19.4. Affected by this issue is the function rand_str of the file cloudinit/util.py of the component Mersenne Twister Handler. The manipulation results in random values (PRNG). This vulnerability is known as CVE-2020-8631. Attacking locally is a requirement. No exploit is available.

Detailsinfo

A vulnerability, which was classified as critical, was found in cloud-init up to 19.4 (Cloud Software). Affected is the function rand_str of the file cloudinit/util.py of the component Mersenne Twister Handler. The manipulation with an unknown input leads to a random values vulnerability (PRNG). CWE is classifying the issue as CWE-330. The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

cloud-init through 19.4 relies on Mersenne Twister for a random password, which makes it easier for attackers to predict passwords, because rand_str in cloudinit/util.py calls the random.choice function.

The weakness was published 02/05/2020. This vulnerability is traded as CVE-2020-8631 since 02/05/2020. The exploitability is told to be easy. The attack needs to be approached locally. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1600.001.

The vulnerability scanner Nessus provides a plugin with the ID 266234 (NewStart CGSL MAIN 6.06 : cloud-init Multiple Vulnerabilities (NS-SA-2025-0230)), which helps to determine the existence of the flaw in a target environment.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at Tenable (266234). Similar entry is available at VDB-149701. Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.4
VulDB Meta Temp Score: 5.3

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

NVD Base Score: 5.5
NVD Vector: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

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

NVD Base Score: 🔍

Exploitinginfo

Name: PRNG
Class: Random values / PRNG
CWE: CWE-330 / CWE-310
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: No

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Nessus ID: 266234
Nessus Name: NewStart CGSL MAIN 6.06 : cloud-init Multiple Vulnerabilities (NS-SA-2025-0230)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔍

Patch: github.com

Timelineinfo

02/05/2020 🔍
02/05/2020 +0 days 🔍
02/05/2020 +0 days 🔍
10/02/2025 +2066 days 🔍

Sourcesinfo

Advisory: DLA 2113-1
Status: Confirmed

CVE: CVE-2020-8631 (🔍)
GCVE (CVE): GCVE-0-2020-8631
GCVE (VulDB): GCVE-100-149700
See also: 🔍

Entryinfo

Created: 02/05/2020 17:34
Updated: 10/02/2025 14:17
Changes: 02/05/2020 17:34 (39), 02/05/2020 17:39 (18), 03/28/2024 14:13 (19), 03/28/2024 14:17 (1), 10/02/2025 14:17 (8)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Want to stay up to date on a daily basis?

Enable the mail alert feature now!