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GHSA-mcg6-h362-cmq5
No affected components available
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
- Originally discovered by @ysf at https://www.huntr.dev/bounties/c458b868-63df-414e-af10-47e3745caa1d/
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:
- Open an issue in the Cobbler repository
- Ask in the Gitter/Matrix Chat
- Email us at cobbler.project@gmail.com
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a low impact on the integrity of the data.
Exploitation activity has been observed. Apply available patches or mitigations urgently.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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