Vulnerability Discussion

Once an attacker establishes initial access to a system, the attacker often attempts to create a persistent method of reestablishing access. One way to accomplish this is for the attacker to simply create a new account. Auditing of account creation mitigates this risk.

To address access requirements, many SUSE operating systems may be integrated with enterprise-level authentication/access/auditing mechanisms that meet or exceed access control policy requirements.

Satisfies: SRG-OS-000004-GPOS-00004, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000463-GPOS-00207, SRG-OS-000476-GPOS-00221

Check

Verify the SUSE operating system generates an audit record when modifications occur to the "/etc/shadow" file.

Check that the file is being audited by performing the following command:

> sudo auditctl -l | grep -w '/etc/shadow'

-w /etc/shadow -p wa -k account_mod

If the command does not return a line, this is a finding.

Notes:
The "-k" allows for specifying an arbitrary identifier. The string following "-k" does not need to match the example output above.

Fix

Configure the SUSE operating system to generate an audit record when all modifications to the "/etc/shadow" file occur.

Add or update the following rule to "/etc/audit/rules.d/audit.rules":

-w /etc/shadow -p wa -k account_mod

To reload the rules file, restart the audit daemon

> sudo systemctl restart auditd.service

or issue the following command:

> sudo augenrules --load