Security Patrol: Security Questions & Answers

IBM i (OS/400, i5/OS)
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Q: Our company uses an initial program to control which menu options users can view. The initial menu is set to MAIN (the IBM default) for end users. Our internal audit department has requested that I change the initial menu to *SIGNOFF. Is this change necessary since the initial program prevents the MAIN menu from being displayed?

A: If the initial program terminates for any reason, the initial menu will be displayed. The MAIN menu gives users menu options that allow viewing and deleting files.

The initial program rarely terminates, so the risk is slight. However, I recommend changing the option to *SIGNOFF, the most secure option for an initial menu.

Making the change may be simpler than convincing the audit department that the initial program will never terminate.

Q: Our programmers do not have command line access to our production systems. When an application error occurs, the programmers need command line access and *ALLOBJ authority. Currently, they sign on using the user profile DPSERVICE, which has *ALLOBJ authority. We record commands entered by the DPSERVICE profile by specifying AUDLVL(*CMD) on the Change User Auditing (CHGUSRAUD) command for DPSERVICE. Several programmers know the password for the DPSERVICE profile. We would like to stop using the DPSERVICE profile and have the programmers use their own user profiles. However, we do not want to audit all the commands the programmers enter.

How can we give programmers command line access but only audit commands when the programmer has adopted *ALLOBJ authority?

A: I agree with your plan to stop using a shared user profile like DPSERVICE. Sharing profiles has some major problems.

1. There's no individual accountability for actions. Determining who used the shared profile is difficult.

2. Changing the user profile password periodically is difficult. A change requires notifying all the authorized users.

I have created the Log Command (LOGCMD) command to turn on auditing for a user profile under certain circumstances. What makes the technique work is the Set Profile (QWTSETP) application program interface (API). This API changes a job to run under a specified profile represented by a profile handle that you pass to the API. (For more information on this API, see "Dynamic Change of Group Profile," MC, May 1994 and Security Patrol, MC, December 1994.)

While creating this technique, I found a problem. After running the API, action auditing was no longer active. The problem occurs under certain conditions.

1. A user's level of action auditing has been set with the Change User Auditing (CHGUSRAUD) command.

2. The Get Profile Handle (QSYGETPH) and QWTSETP APIs change the job to run under a specified profile.

3. The original profile and the new profile are the same.

I contacted IBM and, fortunately, they had a PTF that took care of the problem.

Perform the following steps to create the LOGCMD command and its associated programs and to set up your system to make the technique work.

1. Obtain the PTF for the QWTSETP program, load it, and apply it. (It can be applied immediately.) See 1 for the PTF number corresponding to your release.

1. Obtain the PTF for the QWTSETP program, load it, and apply it. (It can be applied immediately.) See Figure 1 for the PTF number corresponding to your release.

2. Create the LOGCMD authorization list that controls which user profiles are allowed to access the command line.

 CRTAUTL AUTL(LOGCMD) + TEXT('Command line + with command logging') + AUT(*EXCLUDE) 

3. Give users who are allowed this access *USE authority to the authorization list.

 ADDAUTLE AUTL(LOGCMD) + USER(pgmr1) + AUT(*USE) 

4. Create the LOGCMD command (see 2) and secure it with the authorization list LOGCMD. (See the compile instructions at the beginning of the source member.) The LOGCMD was created with ALWLMTUSR(*YES) so the command can be entered by a LMTCPB(*YES) user. An alternative is to add the LOGCMD to the programmer's initial program.

4. Create the LOGCMD command (see Figure 2) and secure it with the authorization list LOGCMD. (See the compile instructions at the beginning of the source member.) The LOGCMD was created with ALWLMTUSR(*YES) so the command can be entered by a LMTCPB(*YES) user. An alternative is to add the LOGCMD to the programmer's initial program.

5. Create CL programs CMD008CL (see 3) and CMD009CL (see 4, page 116). Secure the programs with the authorization list LOGCMD you created in step 1, as described in the compile instructions at the beginning of each source member.

5. Create CL programs CMD008CL (see Figure 3) and CMD009CL (see Figure 4, page 116). Secure the programs with the authorization list LOGCMD you created in step 1, as described in the compile instructions at the beginning of each source member.

Program CMD008CL sets the user profile to log commands and swaps the user profile. Program CMD009CL presents a command entry screen to the user.

Program CMD008CL must be owned by a user profile with *ALLOBJ *SECADM, and *AUDIT special authority. (*AUDIT is required by the CHGUSRAUD command; *ALLOBJ and *SECADM are required to get the profile handle with the *NOPWD option.) Program CMD008CL transfers control to program CMD009CL so that the adopted security officer access is not given to users at the command line. If required, the program CMD009CL can adopt a user profile that has *ALLOBJ authority. The create commands in steps 4 and 5 specify AUT(LOGCMD), so the command and programs are secured by the LOGCMD authorization list.


Security Patrol: Security Questions & Answers

Figure 1 PTF Required for QWTSETP program

 OS/400 Release PTF number V2R3 SF22421 V3R05 SF22422 V3R1 SF22423 
Security Patrol: Security Questions & Answers

Figure 2 Command LOGCMD

 /*==================================================================*/ /* To compile: */ /* */ /* CRTCMD CMD(XXX/LOGCMD) PGM(XXX/CMD001CL) + */ /* SRCFILE(XXX/QCMDSRC) ALWLMTUSR(*YES) + */ /* AUT(LOGCMD) */ /* */ /*==================================================================*/ LOGCMD: CMD PROMPT('Log commands entered by User') PARM KWD(HANDLE) TYPE(*CHAR) LEN(12) + CONSTANT(GLOOP) 
Security Patrol: Security Questions & Answers

Figure 3 CL Program CMD008CL

 /*==================================================================*/ /* To compile: */ /* */ /* CRTCLPGM PGM(XXX/CMD008CL) SRCFILE(XXX/QCLSRC) + */ /* USRPRF(*OWNER) LOG(*NO) ALWRTVSRC(*NO) + */ /* AUT(LOGCMD) */ /* */ /*==================================================================*/ CMD008CL: PGM PARM(&HANDLE) DCL VAR(&USER) TYPE(*CHAR) LEN(10) DCL VAR(&HANDLE) TYPE(*CHAR) LEN(12) /* Profile + swap handle without audit */ DCL VAR(&LOGCMD) TYPE(*CHAR) LEN(12) /* Profile + swap handle with AUDLVL(*CMD) */ RTVUSRPRF RTNUSRPRF(&USER) CALL PGM(QSYGETPH) PARM(&USER '*NOPWD' &HANDLE) CHGUSRAUD USRPRF(&USER) AUDLVL(*CMD) CALL PGM(QSYGETPH) PARM(&USER '*NOPWD' &LOGCMD) CHGUSRAUD USRPRF(&USER) AUDLVL(*NONE) CALL PGM(QWTSETP) PARM(&LOGCMD) CALL PGM(QSYRLSPH) PARM(&LOGCMD) TFRCTL PGM(CMD009CL) PARM(&HANDLE) ENDPGM: ENDPGM 
Security Patrol: Security Questions & Answers

Figure 4 CL Program CMD009CL

 /*==================================================================*/ /* To compile: */ /* */ /* CRTCLPGM PGM(XXX/CMD009CL) SRCFILE(XXX/QCLSRC) + */ /* USRPRF(*OWNER) LOG(*NO) ALWRTVSRC(*NO) + */ /* AUT(LOGCMD) */ /* */ /*==================================================================*/ CMD009CL: PGM PARM(&HANDLE) DCL VAR(&HANDLE) TYPE(*CHAR) LEN(12) DCL VAR(&LMTCPB) TYPE(*CHAR) LEN(10) DCL VAR(&MSG) TYPE(*CHAR) LEN(512) DCL VAR(&KEYVAR) TYPE(*CHAR) LEN(4) DCL VAR(&RTNTYPE) TYPE(*CHAR) LEN(2) RTVUSRPRF USRPRF(*CURRENT) LMTCPB(&LMTCPB) IF COND(&LMTCPB *NE '*YES') THEN(DO) CALL PGM(QCMD) /* Command entry screen */ ENDDO ELSE DO /* If user is LMTCPB(*YES) give the user a command */ /* line via QCMDEXC. */ RECEIVE: RCVMSG PGMQ(*EXT) MSGTYPE(*RQS) RMV(*NO) + KEYVAR(&KEYVAR) MSG(&MSG) RTNTYPE(&RTNTYPE) MONMSG MSGID(CPF2415) EXEC(GOTO CMDLBL(EXIT)) /* F3 + = Exit */ IF COND(&RTNTYPE = '10') THEN(CHGVAR VAR(&MSG) + VALUE('?' || &MSG)) CALL PGM(QCMDCHK) PARM(&MSG 512) MONMSG MSGID(CPF0000) EXEC(GOTO CMDLBL(RECEIVE)) RMVMSG PGMQ(*EXT) MSGKEY(&KEYVAR) CLEAR(*BYKEY) SNDPGMMSG MSG(&MSG) TOPGMQ(*EXT) MSGTYPE(*RQS) RCVMSG PGMQ(*EXT) MSGTYPE(*RQS) RMV(*NO) CALL PGM(QCMDEXC) PARM(&MSG 512) MONMSG MSGID(CPF0000) GOTO CMDLBL(RECEIVE) ENDDO EXIT: CALL PGM(QWTSETP) PARM(&HANDLE) CALL PGM(QSYRLSPH) PARM(&HANDLE) ENDPGM 
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