CVE-2021-3429

sensitive data exposure in cloud-init logs

Severity Score

5.5

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Track

*SSVC

Descriptions

When instructing cloud-init to set a random password for a new user account, versions before 21.2 would write that password to the world-readable log file /var/log/cloud-init-output.log. This could allow a local user to log in as another user.

A flaw was found in cloud-init. When a system is configured through cloud-init and the "Set Passwords" module is used with "chpasswd" directive and "RANDOM", the randomly generated password for the relative user is written in clear-text in a file readable by any existing user of the system. The highest threat from this vulnerability is to data confidentiality and it may allow a local attacker to log in as another user.

The cloud-init packages provide a set of init scripts for cloud instances. Cloud instances need special scripts to run during initialization to retrieve and install SSH keys, and to let the user run various scripts.

*Credits: Carl Pearson

CVSS Scores

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

Attack Vector

Local

Attack Complexity

Low

Authentication

Single

Confidentiality

Complete

Integrity

None

Availability

None

Attack Vector

Local

Attack Complexity

Low

Authentication

None

Confidentiality

Partial

Integrity

Partial

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:Track

Exploitation

None

Automatable

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2021-03-10 CVE Reserved
2021-08-10 CVE Published
2025-02-05 CVE Updated
2025-03-30 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-532: Insertion of Sensitive Information into Log File

CAPEC

References (3)

URL	Tag	Source

URL	Date	SRC

URL	Date	SRC
https://github.com/canonical/cloud-init/commit/b794d426b9ab43ea9d6371477466070d86e10668	2023-05-04

URL	Date	SRC
https://access.redhat.com/security/cve/CVE-2021-3429	2021-08-31
https://bugzilla.redhat.com/show_bug.cgi?id=1940967	2021-08-31

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Canonical Search vendor "Canonical"		Cloud-init Search vendor "Canonical" for product "Cloud-init"				< 21.2 Search vendor "Canonical" for product "Cloud-init" and version " < 21.2"		-		Affected