IBM z/OS SSL encryption options for the TN3270 Telnet Server must be specified properly for each statement that defines a SECUREPORT or within the TELNETGLOBALS.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-223610	ACF2-TN-000030	SV-223610r958408_rule		Medium

Description
Without confidentiality protection mechanisms, unauthorized individuals may gain access to sensitive information via a remote access session. Remote access is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Encryption provides a means to secure the remote connection to prevent unauthorized access to the data traversing the remote access connection (e.g., RDP), thereby providing a degree of confidentiality. The encryption strength of a mechanism is selected based on the security categorization of the information. Satisfies: SRG-OS-000033-GPOS-00014, SRG-OS-000120-GPOS-00061, SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174, SRG-OS-000396-GPOS-00176, SRG-OS-000423-GPOS-00187, SRG-OS-000424-GPOS-00188, SRG-OS-000425-GPOS-00189, SRG-OS-000426-GPOS-00190, SRG-OS-000478-GPOS-00223

Description

Without confidentiality protection mechanisms, unauthorized individuals may gain access to sensitive information via a remote access session. Remote access is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include, for example, dial-up, broadband, and wireless. Encryption provides a means to secure the remote connection to prevent unauthorized access to the data traversing the remote access connection (e.g., RDP), thereby providing a degree of confidentiality. The encryption strength of a mechanism is selected based on the security categorization of the information. Satisfies: SRG-OS-000033-GPOS-00014, SRG-OS-000120-GPOS-00061, SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174, SRG-OS-000396-GPOS-00176, SRG-OS-000423-GPOS-00187, SRG-OS-000424-GPOS-00188, SRG-OS-000425-GPOS-00189, SRG-OS-000426-GPOS-00190, SRG-OS-000478-GPOS-00223

STIG	Date
IBM z/OS ACF2 Security Technical Implementation Guide	2024-06-24

Details

Check Text ( C-25283r504791_chk )
Refer to the Profile configuration file specified on the PROFILE DD statement in the TCPIP started task JCL. If the following items are in effect for the configuration specified in the TCP/IP Profile configuration file, this is not a finding. NOTE: If an INCLUDE statement is coded in the TCP/IP Profile configuration file, the data set specified on this statement must be checked for the following items as well. NOTE: FIPS 140-2 minimum encryption is the accepted level of encryption and will override this requirement if greater. The TELNETGLOBALS block that specifies an ENCRYPTION statement states one or more of the below cipher specifications. Each TELNETPARMS block that specifies the SECUREPORT statement, specifies an ENCRYPTION statement that states one or more of the below cipher specifications, and the TELNETGLOBALS block does or does not specify an ENCRYPTION statement. Cipher Specifications SSL_3DES_SHA SSL_AES_256_SHA SSL_AES_128_SHA

Check Text ( C-25283r504791_chk )

Refer to the Profile configuration file specified on the PROFILE DD statement in the TCPIP started task JCL.

If the following items are in effect for the configuration specified in the TCP/IP Profile configuration file, this is not a finding.

NOTE: If an INCLUDE statement is coded in the TCP/IP Profile configuration file, the data set specified on this statement must be checked for the following items as well.

NOTE: FIPS 140-2 minimum encryption is the accepted level of encryption and will override this requirement if greater.

The TELNETGLOBALS block that specifies an ENCRYPTION statement states one or more of the below cipher specifications.

Each TELNETPARMS block that specifies the SECUREPORT statement, specifies an ENCRYPTION statement that states one or more of the below cipher specifications, and the TELNETGLOBALS block does or does not specify an ENCRYPTION statement.

Cipher Specifications
SSL_3DES_SHA
SSL_AES_256_SHA
SSL_AES_128_SHA

Fix Text (F-25271r504792_fix)
Configure the SECUREPORT and TELNETPARMS ENCRYPTION statements and/or the TELNETGLOBALS statement in the PROFILE.TCPIP file to conform to the requirements specified below. The TELNETGLOBALS block may specify an ENCRYPTION statement that specifies one or more of the below cipher specifications. Each TELNETPARMS block that specifies the SECUREPORT statement, an ENCRYPTION statement is coded with one or more of the below cipher specifications, and the TELNETGLOBALS block does or does not specify an ENCRYPTION statement. To prevent the use of non FIPS 140-2 encryption, the TELNETGLOBALS block and/or each TELNETPARMS block that specifies an ENCRYPTION statement will specify one or more of the following cipher specifications: Cipher Specifications SSL_3DES_SHA SSL_AES_256_SHA SSL_AES_128_SHA Note: Always check for the minimum allowed in FIPS 140-2.

Fix Text (F-25271r504792_fix)

Configure the SECUREPORT and TELNETPARMS ENCRYPTION statements and/or the TELNETGLOBALS statement in the PROFILE.TCPIP file to conform to the requirements specified below.

The TELNETGLOBALS block may specify an ENCRYPTION statement that specifies one or more of the below cipher specifications.

Each TELNETPARMS block that specifies the SECUREPORT statement, an ENCRYPTION statement is coded with one or more of the below cipher specifications, and the TELNETGLOBALS block does or does not specify an ENCRYPTION statement.

To prevent the use of non FIPS 140-2 encryption, the TELNETGLOBALS block and/or each TELNETPARMS block that specifies an ENCRYPTION statement will specify one or more of the following cipher specifications:

Cipher Specifications
SSL_3DES_SHA
SSL_AES_256_SHA
SSL_AES_128_SHA

Note: Always check for the minimum allowed in FIPS 140-2.