STIGQter: STIG Summary: IBM z/OS ACF2 Security Technical Implementation Guide Version: 9 Release: 9 Benchmark Date: 01 Jul 2026:

IBM z/OS SSH daemon must be configured to use a FIPS 140-3-compliant cryptographic algorithm.

DISA Rule

SV-223589r1225812_rule

Vulnerability Number

V-223589

Group Title

SRG-OS-000033-GPOS-00014

Rule Version

ACF2-SH-000050

Severity

CAT I

CCI(s)

• CCI-000068 - Implement cryptographic mechanisms to protect the confidentiality of remote access sessions.
• CCI-000803 - Implement mechanisms for authentication to a cryptographic module that meet the requirements of applicable laws, Executive Orders, directives, policies, regulations, standards, and guidance for such authentication.
• CCI-001453 - Implement cryptographic mechanisms to protect the integrity of remote access sessions.

Weight

10

Fix Recommendation

Edit the SSH daemon configuration and remove any ciphers not starting with "aes". If necessary, add a "Ciphers" line using FIPS 140-3-compliant algorithms.

Configure for message authentication to MACs "hmac-sha1" or greater.

Edit the z/OS-specific sshd server systemwide configuration file configuration as follows:
FIPSMODE=YES
CiphersSource=ICSF
MACsSource=ICSF

Check Contents

Locate the SSH daemon configuration file, which may be found in "/etc/ssh/" directory.

Alternately:

From the UNIX System Services ISPF Shell, navigate to ribbon select tools.

Select option 1 - Work with Processes.

If SSH Daemon is not active, this is not a finding.

Examine the SSH daemon configuration file:
sshd_config

If there are no ciphers lines, or the ciphers list contains any cipher not starting with "aes", this is a finding.

If the MACs line is not configured to "hmac-sha1" or greater, this is a finding.

Examine the z/OS-specific sshd server systemwide configuration:
zos_sshd_config

If any of the following is untrue, this is a finding:

FIPSMODE=YES
CiphersSource=ICSF
MACsSource=ICSF

Vulnerability Number

V-223589

Documentable

False

Rule Version

ACF2-SH-000050

Severity Override Guidance

Locate the SSH daemon configuration file, which may be found in "/etc/ssh/" directory.

Alternately:

From the UNIX System Services ISPF Shell, navigate to ribbon select tools.

Select option 1 - Work with Processes.

If SSH Daemon is not active, this is not a finding.

Examine the SSH daemon configuration file:
sshd_config

If there are no ciphers lines, or the ciphers list contains any cipher not starting with "aes", this is a finding.

If the MACs line is not configured to "hmac-sha1" or greater, this is a finding.

Examine the z/OS-specific sshd server systemwide configuration:
zos_sshd_config

If any of the following is untrue, this is a finding:

FIPSMODE=YES
CiphersSource=ICSF
MACsSource=ICSF

Check Content Reference

M

Target Key

4100