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Improper Authorization in cobbler

High severity GitHub Reviewed Published Mar 11, 2022 in cobbler/cobbler • Updated Jan 27, 2023

Package

pip cobbler (pip)

Affected versions

< 3.3.2

Patched versions

3.3.2

Description

Impact

If PAM is correctly configured and a user account is set to expired, the expired user-account is still able to successfully log into Cobbler in all places (Web UI, CLI & XMLRPC-API).

The same applies to user accounts with passwords set to be expired.

Patches

There is a patch for the latest Cobbler 3.3.2 available, however a backport will be done for 3.2.x.

Workarounds

  • Delete expired accounts which are able to access Cobbler via PAM.
  • Use chage -l <username> to lock the account. If the account has SSH-Keys attached then remove them completely.

References

How to test if my Cobbler instance is affected?

The following pytest test assumes that your PAM setup is correct. In case the added user is not able to login, this test does not make sense to be executed.

def test_pam_login_with_expired_user():
    # Arrange
    # create pam testuser
    test_username = "expired_user"
    test_password = "password"
    test_api = CobblerAPI()
    subprocess_1 = subprocess.run(
        ["perl", "-e", "'print crypt(\"%s\", \"%s\")'" % (test_username, test_password)],
        stdout=subprocess.PIPE
    )
    subprocess.run(["useradd", "-p", subprocess_1.stdout, test_username])
    # change user to be expired
    subprocess.run(["chage", "-E0", test_username])

    # Act
    result = pam.authenticate(test_api, test_username, test_password)

    # Assert - login should fail
    assert not result

For more information

If you have any questions or comments about this advisory:

References

@SchoolGuy SchoolGuy published to cobbler/cobbler Mar 11, 2022
Published by the National Vulnerability Database Mar 11, 2022
Published to the GitHub Advisory Database Mar 11, 2022
Reviewed Mar 11, 2022
Last updated Jan 27, 2023

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
Low
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

EPSS score

0.178%
(56th percentile)

Weaknesses

CVE ID

CVE-2022-0860

GHSA ID

GHSA-mcg6-h362-cmq5

Source code

Credits

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