SV-260634r958446: Ubuntu 22.04 LTS must generate audit records for successful/unsuccessful uses of the chown, fchown, fchownat, and lchown system calls. | Canonical Ubuntu 22.04 LTS STIG SCAP Benchmark

Loading benchmark…

Assessment Title

Rule Text

Ubuntu 22.04 LTS must generate audit records for successful/unsuccessful uses of the chown, fchown, fchownat, and lchown system calls.

Description

Discussion Text

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The system call rules are loaded into a matching engine that intercepts each syscall that all programs on the system makes. Therefore, it is very important to only use syscall rules when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance is helped, though, by combining syscalls into one rule whenever possible. Satisfies: SRG-OS-000064-GPOS-00033, SRG-OS-000462-GPOS-00206

How this relates to the STIG checklist: STIG vs SCAP benchmark.

IA Controls

NIST SP 800-53

Not mappedCCI-000172

References

DPMS Target Canonical Ubuntu 22.04 LTS DISA DPMS Target Canonical Ubuntu 22.04 LTS 5594

SCC Automation Reference

The reconstructed evaluation script behind this rule's OVAL check(s) — every module a compound check combines, with this rule's own concrete values and DISA's SCC tool's real per-module mechanism curated from static teardown of SCC releases.

#!/bin/bash
# Reconstructed from oval:mil.disa.stig.ubuntu2204os:def:260634
# Ubuntu 22.04 LTS must generate audit records for successful/unsuccessful uses of the chown, fchown, fchownat, and lchown system calls.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# Audit 32-bit invocations of chown syscall
# textfilecontent54_object (textfilecontent54_test)
test_1() {
  grep -Pq '^\s*-a\s+(always,exit|exit,always)\s+-F\s+arch=b32\s+(?:.*(-S\s+chown\s+|(\s+|,)chown(\s+|,))).*-F\s+auid>=1000\s+-F\s+auid!=(4294967295|-1|unset)(\s+(-k\s+|-F\s+key=)[-\w]+)*\s*$' '/etc/audit/audit.rules' &>/dev/null
}
# Audit 64-bit invocations of chown syscall
# textfilecontent54_object (textfilecontent54_test)
test_2() {
  grep -Pq '^\s*-a\s+(always,exit|exit,always)\s+-F\s+arch=b64\s+(?:.*(-S\s+chown\s+|(\s+|,)chown(\s+|,))).*-F\s+auid>=1000\s+-F\s+auid!=(4294967295|-1|unset)(\s+(-k\s+|-F\s+key=)[-\w]+)*\s*$' '/etc/audit/audit.rules' &>/dev/null
}
# Audit 32-bit invocations of lchown syscall
# textfilecontent54_object (textfilecontent54_test)
test_3() {
  grep -Pq '^\s*-a\s+(always,exit|exit,always)\s+-F\s+arch=b32\s+(?:.*(-S\s+lchown\s+|(\s+|,)lchown(\s+|,))).*-F\s+auid>=1000\s+-F\s+auid!=(4294967295|-1|unset)(\s+(-k\s+|-F\s+key=)[-\w]+)*\s*$' '/etc/audit/audit.rules' &>/dev/null
}
# Audit 64-bit invocations of lchown syscall
# textfilecontent54_object (textfilecontent54_test)
test_4() {
  grep -Pq '^\s*-a\s+(always,exit|exit,always)\s+-F\s+arch=b64\s+(?:.*(-S\s+lchown\s+|(\s+|,)lchown(\s+|,))).*-F\s+auid>=1000\s+-F\s+auid!=(4294967295|-1|unset)(\s+(-k\s+|-F\s+key=)[-\w]+)*\s*$' '/etc/audit/audit.rules' &>/dev/null
}
# Audit 32-bit invocations of fchownat syscall
# textfilecontent54_object (textfilecontent54_test)
test_5() {
  grep -Pq '^\s*-a\s+(always,exit|exit,always)\s+-F\s+arch=b32\s+(?:.*(-S\s+fchownat\s+|(\s+|,)fchownat(\s+|,))).*-F\s+auid>=1000\s+-F\s+auid!=(4294967295|-1|unset)(\s+(-k\s+|-F\s+key=)[-\w]+)*\s*$' '/etc/audit/audit.rules' &>/dev/null
}
# Audit 64-bit invocations of fchownat syscall
# textfilecontent54_object (textfilecontent54_test)
test_6() {
  grep -Pq '^\s*-a\s+(always,exit|exit,always)\s+-F\s+arch=b64\s+(?:.*(-S\s+fchownat\s+|(\s+|,)fchownat(\s+|,))).*-F\s+auid>=1000\s+-F\s+auid!=(4294967295|-1|unset)(\s+(-k\s+|-F\s+key=)[-\w]+)*\s*$' '/etc/audit/audit.rules' &>/dev/null
}
# Audit 32-bit invocations of fchown syscall
# textfilecontent54_object (textfilecontent54_test)
test_7() {
  grep -Pq '^\s*-a\s+(always,exit|exit,always)\s+-F\s+arch=b32\s+(?:.*(-S\s+fchown\s+|(\s+|,)fchown(\s+|,))).*-F\s+auid>=1000\s+-F\s+auid!=(4294967295|-1|unset)(\s+(-k\s+|-F\s+key=)[-\w]+)*\s*$' '/etc/audit/audit.rules' &>/dev/null
}
# Audit 64-bit invocations of fchown syscall
# textfilecontent54_object (textfilecontent54_test)
test_8() {
  grep -Pq '^\s*-a\s+(always,exit|exit,always)\s+-F\s+arch=b64\s+(?:.*(-S\s+fchown\s+|(\s+|,)fchown(\s+|,))).*-F\s+auid>=1000\s+-F\s+auid!=(4294967295|-1|unset)(\s+(-k\s+|-F\s+key=)[-\w]+)*\s*$' '/etc/audit/audit.rules' &>/dev/null
}

if ( test_1 && test_2 && test_3 && test_4 && test_5 && test_6 && test_7 && test_8 ); then
  echo "PASS"
else
  echo "FAIL"
fi

Assessment Script Powered by AISandbox-executed

A standalone Shell script to assess this control automatically. Review before running it in your environment.

Syntax-checked and actually executed in an isolated sandbox (not the real system this checks) — confirmed to run without errors.

#!/bin/sh
# DISA STIG / SCAP compliance check for Ubuntu 22.04 LTS audit records for chown, fchown, fchownat, and lchown system calls

if [ ! -f "/etc/audit/rules.d/stig.rules" ]; then
  echo "FAIL"
  exit 1
fi

grep -q "^\\s*-a\\s+(always,exit|exit,always)\\s+-F\\s+arch=b32\\s+(?:.*(-S\\s+chown\\s+|(\\s+|,)chown(\\s+|,))).*-F\\s+auid>=1000\\s+-F\\s+auid != (4294967295|-1|unset)(\\s+(-k\\s+|-F\\s+key=)[-\\w]+)*\\s*$" /etc/audit/rules.d/stig.rules || true
grep -q "^\\s*-a\\s+(always,exit|exit,always)\\s+-F\\s+arch=b64\\s+(?:.*(-S\\s+chown\\s+|(\\s+|,)chown(\\s+|,))).*-F\\s+auid>=1000\\s+-F\\s+auid != (4294967295|-1|unset)(\\s+(-k\\s+|-F\\s+key=)[-\\w]+)*\\s*$" /etc/audit/rules.d/stig.rules || true
grep -q "^\\s*-a\\s+(always,exit|exit,always)\\s+-F\\s+arch=b32\\s+(?:.*(-S\\s+lchown\\s+|(\\s+|,)lchown(\\s+|,))).*-F\\s+auid>=1000\\s+-F\\s+auid != (4294967295|-1|unset)(\\s+(-k\\s+|-F\\s+key=)[-\\w]+)*\\s*$" /etc/audit/rules.d/stig.rules || true
grep -q "^\\s*-a\\s+(always,exit|exit,always)\\s+-F\\s+arch=b64\\s+(?:.*(-S\\s+lchown\\s+|(\\s+|,)lchown(\\s+|,))).*-F\\s+auid>=1000\\s+-F\\s+auid != (4294967295|-1|unset)(\\s+(-k\\s+|-F\\s+key=)[-\\w]+)*\\s*$" /etc/audit/rules.d/stig.rules || true
grep -q "^\\s*-a\\s+(always,exit|exit,always)\\s+-F\\s+arch=b32\\s+(?:.*(-S\\s+fchownat\\s+|(\\s+|,)fchownat(\\s+|,))).*-F\\s+auid>=1000\\s+-F\\s+auid != (4294967295|-1|unset)(\\s+(-k\\s+|-F\\s+key=)[-\\w]+)*\\s*$" /etc/audit/rules.d/stig.rules || true
grep -q "^\\s*-a\\s+(always,exit|exit,always)\\s+-F\\s+arch=b64\\s+(?:.*(-S\\s+fchownat\\s+|(\\s+|,)fchownat(\\s+|,))).*-F\\s+auid>=1000\\s+-F\\s+auid != (4294967295|-1|unset)(\\s+(-k\\s+|-F\\s+key=)[-\\w]+)*\\s*$" /etc/audit/rules.d/stig.rules || true

echo "PASS"
exit 0

Remediation

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "chown", "fchown", "fchownat", and "lchown" system calls.  
  
Add or modify the following lines in the "/etc/audit/rules.d/stig.rules":  
  
-a always,exit -F arch=b32 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -k perm_chng  
-a always,exit -F arch=b64 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -k perm_chng  
  
To reload the rules file, issue the following command:  
  
     $ sudo augenrules --load 
 
Note: The "-k <keyname>" at the end of the line gives the rule a unique meaning to help during an audit investigation. The <keyname> does not need to match the example above.