SV-38677r2: The system must require at least eight characters be changed between the old and new passwords during a password change. | AIX 6.1 SECURITY TECHNICAL IMPLEMENTATION GUIDE

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Assessment Title

Rule Text

The system must require at least eight characters be changed between the old and new passwords during a password change.

Description

Discussion Text

To ensure password changes are effective in their goals, the system must ensure old and new passwords have significant differences. Without significant changes, new passwords may be easily guessed based on the value of a previously compromised password.

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

IA Controls

NIST SP 800-53

Not mappedCCI-000195

Additional Details

Responsibility

System Administrator

References

DPMS Target AIX 6.1 DISA DPMS Target AIX 6.1 2176

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.fso.aix11:def:49
# The system must require at least eight characters be changed between the old and new passwords during a password change.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# all instances of mindiff are OK
# textfilecontent54_object (textfilecontent54_test)
test_1() {
  [ "$(sed -En 's/^[ 	]*mindiff[ 	]*=[ 	]*([0-9]+)/\1/p' '/etc/security/user')" -ge 8 ]
}
# default specifies mindiff
# textfilecontent54_object (textfilecontent54_test)
test_2() {
  (sed -En 's/^([^: 	
]+):
([^:
]+=[^
]*
)*[ 	]*mindiff = [0-9]+/\1/p' '/etc/security/user') | grep -qxF 'default'
}
# all users specify mindiff
# password_object (password_test)
test_3() {
  ! ( getent passwd .* &>/dev/null )
}

if ( test_1 && ( test_2 || test_3 ) ); 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
# oval:mil.disa.fso.aix11:def:49

if grep -q '^[ \t]*mindiff[ \t]*=[ \t]*8' /etc/security/user; then
    echo "PASS"
    exit 0
fi

if grep -E '^([^: \t\n]+):\n[^:\n]+=[^\n]*\n[ \t]*mindiff = 8' /etc/security/user; then
    echo "PASS"
    exit 0
fi

echo "FAIL"
exit 1

Remediation

Use the chsec command to change mindiff to 8.

# chsec -f /etc/security/user -s default -a mindiff=8

# chuser mindiff=8 < user id >