03
Sun, Mar
0 New Articles

Security Patrol

IBM i (OS/400, i5/OS)
Typography
  • Smaller Small Medium Big Bigger
  • Default Helvetica Segoe Georgia Times

Q: I recently received a letter from IBM about some security-related fixes for my AS/400 (see "How Secure Is Your AS/400?" Significa, MC, September 1995). The letter, dated July 21, did not describe the changes. Are you aware of the details? Should I apply the changes?

A: I talked with the IBM security team about the security-related changes. IBM recognizes that, with the increased interconnection of AS/400s (including the Internet), there is an increased risk from outside hackers. These PTFs help reduce the security exposures, and you should apply them to your system. I'll explain the details of the changes made when you apply the PTFs, but first let me recommend that all AS/400 installations take the following steps immediately to reduce security exposures:

1. Order the security PTF associated with the different OS/400 releases listed in 1 and you automatically receive any corequisite PTFs. Apply all the PTFs that you receive.

1. Order the security PTF associated with the different OS/400 releases listed in Figure 1 and you automatically receive any corequisite PTFs. Apply all the PTFs that you receive.

2. Change all default passwords.

3. Install an exit program to prevent use of the Submit Remote Command (SBMRMTCMD) command. If preventing remote commands is not possible, use the exit program to record the remote commands and review the commands.

4. Increase system security level to 40.

The following details and background information explain why the changes should be made.

Change Default Passwords

The PTF cover letter recommends that you change the password of all IBM profiles. This is very important, as illustrated by the following actual experience.

When I do a security review on clients' AS/400s, I sometimes try to guess the password of some of the IBM-provided user profiles. I often find the password of the QSRV user profile is left unchanged or is some trivial value such as IBM or SERVICE.

The default passwords for all IBM profiles and any vendor software should be changed or set to *NONE. It is critical that you change the password for the following IBM system-supplied profiles: QSECOFR, QSRV, QSRVBAS, QPGMR, QUSER, and QSYSOPR. The user profile QSRV is a large exposure because installations fail to change the password, and the QSRV profile can use service tools to view and modify any object on the system. Eliminating trivial and default passwords is essential to protecting your AS/400.

Prevent Remote Commands

A method to gain access to a remote AS/400 is to create a DDM file. The DDM file can be used on SBMRMTCMD to issue commands on the remote system. If the remote system does not include an exit program to prevent remote commands, the commands are run as the default user (usually the QUSER user profile). SBMRMTCMD can also be used to send commands to the remote system. These commands could display information about communication connections. Then the print files could be sent back to the local AS/400.

I recommend creating an exit program to prevent the use of remote commands on your AS/400 (see 2 for a sample exit program). The exit program is specified on the DDM request access (DDMACC) parameter of the Change Network Attributes (CHGNETA) command. For more information on restricting DDM users' access to your system through exit programs, see the Distributed Data Management manual.

I recommend creating an exit program to prevent the use of remote commands on your AS/400 (see Figure 2 for a sample exit program). The exit program is specified on the DDM request access (DDMACC) parameter of the Change Network Attributes (CHGNETA) command. For more information on restricting DDM users' access to your system through exit programs, see the Distributed Data Management manual.

Limit Configuration Commands

One of the changes made by the IBM PTF limits access to the commands that can be used to configure APPC communications. The *PUBLIC access to these commands is revoked, preventing the QUSER user profile from being able to create or change APPC configuration objects on a target system. After the PTF is applied, the user must have authority to the commands and object management (*OBJMGT) authority to change any existing APPC configuration object. When you apply the PTF for a V3R1 system, the commands required to configure APPC communications will require the special authority *IOSYSCFG in addition to *OBJMGT authority.

Limit Access to QCPFMSG

The PTF changes the *PUBLIC access to the message file QCPFMSG to *USE. Some OS/400 components retrieve messages from QCPFMSG which represent the commands issued when a user selects an option from an IBM menu. With *CHANGE access, a hacker could possibly change the message file to cause a different command to be issued.

Change to Security Level 40

Most AS/400 installations use security level 30. However, security level 40 provides some important protections. (Moving to level 40 is described in "A Guide to Changing QSECURITY," MC, March 1994.) For instance, with level 40, jobs submitted with a JOBD (job description) that names a user profile require that the user have access to both the JOBD and the user profile. If you are not running level 40 security, a hacker can find a JOBD that names a user profile and use that JOBD to run jobs as another user. For example, the user profile for the QBATCH JOBD in library QGPL is QPGMR, and QPGMR usually has a significant degree of authority.

References

Client Access/400 for DOS and OS/2 Technical Reference (SC41-3563, CD-ROM QBKAKV01).

Distributed Data Management (SC41-3307, CD-ROM QBKALH00).

Security Reference (SC41-3302, CD-ROM QBKALC00).


Security Patrol

Figure 1: Security PTFs

 OS/400 PTF Number Release V3R1 SF23871 V3R0M5 SF23873 V2R3 SF23874 V2R2 SF24390 
Security Patrol

Figure 2: Exit Program RMT001CL

 /**************************************************************************/ /* Installation instructions */ /* 1. Compile program */ /* CRTCLPGM PGM(XXX/RMT001CL) SRCFILE(QCLSRC) */ /* 2 Change network attributes to specify exit program */ /* CHGNETA DDMACC(XXX/RMT001CL) PCSACC(XXX/RMT001CL) */ /* */ /* The program will write entries in the audit journal QAUDJRN. */ /* 'X1' = Requests that are allowed (*LMSRV not logged) */ /* 'X0' = Requests that are rejected */ /**************************************************************************/ PGM PARM(&RC &STRUC) DCL VAR(&RC) TYPE(*CHAR) LEN(1) /*Return code + 1=allow, 0=prevent */ DCL VAR(&STRUC) TYPE(*CHAR) LEN(174) /*Request + description */ DCL VAR(&USER) TYPE(*CHAR) LEN(10) DCL VAR(&APP1) TYPE(*CHAR) LEN(10) DCL VAR(&APP2) TYPE(*CHAR) LEN(10) DCL VAR(&ENTTYP) TYPE(*CHAR) LEN(2) MONMSG MSGID(CPF0000) EXEC(GOTO CMDLBL(EXIT)) CHGVAR VAR(&RC) VALUE('1') /* Allow request */ CHGVAR VAR(&USER) VALUE(%SST(&STRUC 1 10)) CHGVAR VAR(&APP1) VALUE(%SST(&STRUC 11 10)) CHGVAR VAR(&APP2) VALUE(%SST(&STRUC 21 10)) /************************************************/ /* Do not log IBM request to check license */ /************************************************/ IF COND(&APP1 = '*LMSRV') THEN(GOTO CMDLBL(EXIT)) /************************************************/ /* Allow requests for selected users */ /************************************************/ IF COND(&USER = 'XXXXXXXXX') THEN(GOTO + CMDLBL(LOG)) /***********************************************/ /* Prevent use of remote commands */ /***********************************************/ IF COND(&APP1 = '*DDM' *AND &APP2 = 'COMMAND') + THEN(DO) CHGVAR VAR(&RC) VALUE('0') GOTO CMDLBL(LOG) ENDDO /************************************************/ /* Prevent file down upload from PC users */ /************************************************/ IF COND(&APP1 = '*TFRCTL' *AND &APP2 = + 'REPLACE') THEN(DO) CHGVAR VAR(&RC) VALUE('0') GOTO CMDLBL(LOG) ENDDO /******************************************************/ /* Log request X1=allow request X0=prevent request */ /******************************************************/ LOG: CHGVAR VAR(&ENTTYP) VALUE('X' *CAT &RC) SNDJRNE JRN(QAUDJRN) TYPE(&ENTTYP) ENTDTA(&STRUC) EXIT: ENDPGM 
BLOG COMMENTS POWERED BY DISQUS

LATEST COMMENTS

Support MC Press Online

$0.00 Raised:
$

Book Reviews

Resource Center

  • SB Profound WC 5536 Have you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application. You can find Part 1 here. In Part 2 of our free Node.js Webinar Series, Brian May teaches you the different tooling options available for writing code, debugging, and using Git for version control. Brian will briefly discuss the different tools available, and demonstrate his preferred setup for Node development on IBM i or any platform. Attend this webinar to learn:

  • SB Profound WP 5539More than ever, there is a demand for IT to deliver innovation. Your IBM i has been an essential part of your business operations for years. However, your organization may struggle to maintain the current system and implement new projects. The thousands of customers we've worked with and surveyed state that expectations regarding the digital footprint and vision of the company are not aligned with the current IT environment.

  • SB HelpSystems ROBOT Generic IBM announced the E1080 servers using the latest Power10 processor in September 2021. The most powerful processor from IBM to date, Power10 is designed to handle the demands of doing business in today’s high-tech atmosphere, including running cloud applications, supporting big data, and managing AI workloads. But what does Power10 mean for your data center? In this recorded webinar, IBMers Dan Sundt and Dylan Boday join IBM Power Champion Tom Huntington for a discussion on why Power10 technology is the right strategic investment if you run IBM i, AIX, or Linux. In this action-packed hour, Tom will share trends from the IBM i and AIX user communities while Dan and Dylan dive into the tech specs for key hardware, including:

  • Magic MarkTRY the one package that solves all your document design and printing challenges on all your platforms. Produce bar code labels, electronic forms, ad hoc reports, and RFID tags – without programming! MarkMagic is the only document design and print solution that combines report writing, WYSIWYG label and forms design, and conditional printing in one integrated product. Make sure your data survives when catastrophe hits. Request your trial now!  Request Now.

  • SB HelpSystems ROBOT GenericForms of ransomware has been around for over 30 years, and with more and more organizations suffering attacks each year, it continues to endure. What has made ransomware such a durable threat and what is the best way to combat it? In order to prevent ransomware, organizations must first understand how it works.

  • SB HelpSystems ROBOT GenericIT security is a top priority for businesses around the world, but most IBM i pros don’t know where to begin—and most cybersecurity experts don’t know IBM i. In this session, Robin Tatam explores the business impact of lax IBM i security, the top vulnerabilities putting IBM i at risk, and the steps you can take to protect your organization. If you’re looking to avoid unexpected downtime or corrupted data, you don’t want to miss this session.

  • SB HelpSystems ROBOT GenericCan you trust all of your users all of the time? A typical end user receives 16 malicious emails each month, but only 17 percent of these phishing campaigns are reported to IT. Once an attack is underway, most organizations won’t discover the breach until six months later. A staggering amount of damage can occur in that time. Despite these risks, 93 percent of organizations are leaving their IBM i systems vulnerable to cybercrime. In this on-demand webinar, IBM i security experts Robin Tatam and Sandi Moore will reveal:

  • FORTRA Disaster protection is vital to every business. Yet, it often consists of patched together procedures that are prone to error. From automatic backups to data encryption to media management, Robot automates the routine (yet often complex) tasks of iSeries backup and recovery, saving you time and money and making the process safer and more reliable. Automate your backups with the Robot Backup and Recovery Solution. Key features include:

  • FORTRAManaging messages on your IBM i can be more than a full-time job if you have to do it manually. Messages need a response and resources must be monitored—often over multiple systems and across platforms. How can you be sure you won’t miss important system events? Automate your message center with the Robot Message Management Solution. Key features include:

  • FORTRAThe thought of printing, distributing, and storing iSeries reports manually may reduce you to tears. Paper and labor costs associated with report generation can spiral out of control. Mountains of paper threaten to swamp your files. Robot automates report bursting, distribution, bundling, and archiving, and offers secure, selective online report viewing. Manage your reports with the Robot Report Management Solution. Key features include:

  • FORTRAFor over 30 years, Robot has been a leader in systems management for IBM i. With batch job creation and scheduling at its core, the Robot Job Scheduling Solution reduces the opportunity for human error and helps you maintain service levels, automating even the biggest, most complex runbooks. Manage your job schedule with the Robot Job Scheduling Solution. Key features include:

  • LANSA Business users want new applications now. Market and regulatory pressures require faster application updates and delivery into production. Your IBM i developers may be approaching retirement, and you see no sure way to fill their positions with experienced developers. In addition, you may be caught between maintaining your existing applications and the uncertainty of moving to something new.

  • LANSAWhen it comes to creating your business applications, there are hundreds of coding platforms and programming languages to choose from. These options range from very complex traditional programming languages to Low-Code platforms where sometimes no traditional coding experience is needed. Download our whitepaper, The Power of Writing Code in a Low-Code Solution, and:

  • LANSASupply Chain is becoming increasingly complex and unpredictable. From raw materials for manufacturing to food supply chains, the journey from source to production to delivery to consumers is marred with inefficiencies, manual processes, shortages, recalls, counterfeits, and scandals. In this webinar, we discuss how:

  • The MC Resource Centers bring you the widest selection of white papers, trial software, and on-demand webcasts for you to choose from. >> Review the list of White Papers, Trial Software or On-Demand Webcast at the MC Press Resource Center. >> Add the items to yru Cart and complet he checkout process and submit

  • Profound Logic Have you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application.

  • SB Profound WC 5536Join us for this hour-long webcast that will explore:

  • Fortra IT managers hoping to find new IBM i talent are discovering that the pool of experienced RPG programmers and operators or administrators with intimate knowledge of the operating system and the applications that run on it is small. This begs the question: How will you manage the platform that supports such a big part of your business? This guide offers strategies and software suggestions to help you plan IT staffing and resources and smooth the transition after your AS/400 talent retires. Read on to learn: