A nice feature in ABAP is the where used function on usage of programs, tables fields etc, in both standard can custom code. For this function to work properly the ABAP where used index must be up-to-date.
This blog will give answers to the following questions:
How to re-run the ABAP where used index?
How to speed up the ABAP where used index by running in parallel mode?
Which bug fix notes should I apply to get a good ABAP where used index?
How to run ABAP where used index?
You can run the programs SAPRSEUB and SAPRSEUC yourself in background, or start program SAPRSEUJ to schedule the jobs for you.
Program SAPRSEUB will index standard SAP objects. Program SAPRSEUC will index custom objects.
If for whatever reason you want to stop the jobs, use program SAPRSEUB_STOP.
Performance of the where used jobs using parallel processing
Check if OSS note 2228460 – Runtime of job EU_INIT, SAPRSEUB, performance is applied. Using settings in table RSEUPACTRL you can control the runtime behavior of the parallel execution of the where used indexing process. You can check in SM50 and SM66 if the job is using the parallel
OSS notes with bug fixes
The following bug fix OSS notes can be check if they are valid for your release:
Most people underestimate how easy it is to gain access from one client to another client. This blog will explain how easy it is to do it.
Questions that will be answered in this blog are:
How to execute a cross client access hack?
How to detect this attack?
What preventive measures should I take to prevent this in my systems?
Cross client hack explained
You have gained access to a maintenance client by any method (most easy is standard users: see blog on this topic). Some basis and security people will waive this away and say: “by having access to client 066 the hacker cannot do anything, since the real business data is stored into a different client”.
So what the hacker will do is simple open the system client for ABAP coding (SCC4 client opening works from any client). Then he loads this simple program:
REPORT ZSWAPUSER.
data: zls_usr02_1 type usr02.
data: zls_usr02_2 type usr02.
data: zls_usr02_t type usr02.
parameters p_uname1 type usr02-bname.
parameters p_mandt1 type sy-mandt.
parameters p_mandt2 type sy-mandt.
select single * from usr02 client specified into zls_usr02_1 where bname eq p_uname1 and mandt = p_mandt1.
select single * from usr02 client specified into zls_usr02_2 where bname eq p_uname1 and mandt = p_mandt2.
zls_usr02_t = zls_usr02_1. zls_usr02_t-mandt = p_mandt2. modify usr02 client specified from zls_usr02_t.
write sy-subrc.
zls_usr02_t = zls_usr02_2. zls_usr02_t-mandt = p_mandt1.
modify usr02 client specified from zls_usr02_t.
write sy-subrc.
In the source client hacked a new user will be created. Let’s say the user ADMIN, which is also existing in the target client. The hacker creates the user ans sets the password in the source client he has access to. Now he runs the program. The program simply reads the password cross client (yes, ABAP can do cross client reading and updating), and then swaps them…..
After the swap the hacker will logon to the target client with the password he has set and enjoys all the roles from the user ADMIN. After he is done, he simply runs the program again. Then the old password is put back again.
Detecting this attack
Detecting this attack directly is very difficult. There are traces:
Client opening and closing in the source client
The presence of the ABAP code
The ABAP action in the source client’s audit log (you did switch on the audit log in all clients, didn’t you? And if you didn’t read this blog how to do it and execute it!)
ADMIN access from same terminal as the hacker is using to logon to the source client
Preventive measures
The following preventive measures can be taken:
Reset all standard passwords in all systems in all clients (see blog)
Delete no longer needed clients 001 and 066 (see blog)
There are 2 good reasons for mass locking and ending validity date of user: security and licenses.
Questions that will be answered in this blog are:
How can I mass lock users automatically if they have not logged on for a certain time?
How can I mass set the validity date of the users that did not log on for a certain time?
Automatic lock of user after expired logon
In RZ11 you can set parameter login/password_max_idle_productive with an amount in days.
If the user (including yourself) did not logon to the system after this amount of days the password is still valid, but it does not allow you to logon.
If the user tries to logon after the period he will see this error message and cannot continue:
In SU01 such a user looks like this:
If you also want to automatically lock users after you give them a new password, use the parameter login/password_max_idle_initial.
Initial passwords is one of the nice ways of entering a system as hacker. Especially if the initial password used by the admin is more or less the same (like Welcome_1234!). Countermeasure: instruct your admins to use the Password Generator. This will generate long random once off password.
Mass setting of user validity date
For user measurement and security reasons you want to limit the validity period as well. Users who are locked still count for user measurement (see blog on license measurement tips & tricks). Users locked and unlocked by some method can be security threat.
Standard SAP program RSUSR_LOCK_USERS (built on top of program RSUSR200) is the tool to achieve this.
It has quite a long selection screen:
On the first block set the dates for last logon and password change to get a good selection of users.
On the second block very important to only select Dialog Users.
First run with Test Selection to get a list. If you are happy with the list, run it with Set End Of Validity Period.
OSS notes
Performance and bug notes (OSS search hints RSUSR200 and RSUSR_LOCK_USERS):
How to test the deletion before executing in a productive environment?
Why delete clients 001 and 066?
The clients 001 and 066 had a purpose in the past and do not have them any more.
The only thing they do now is pose a security threat. Access can be gained to these clients, for example via standard SAP users, and from these client you could take over the system via a cross client attack. Background on client 066 can be found in OSS note 1897372 – EarlyWatch Mandant 066 – Can Client 066 be deleted?.
Also unwanted batch jobs might be still running from these clients consuming resources.
The deletion can be tested on a development and QA system before it is done on productive system. If really in doubt copy the productive system to a different system and perform the deletion there first as a test.
This blog series will explain the process of hacking SAP password hashes: also know as SAP password hacking. The process of hacking will be explained and appropriate countermeasures will be explained.
In this fourth blog we will continue with more complex attacks on the SAP password hashes and will also explain more preventive measures.
For the first blog on attacking the SAP BCODE hash click here.
For the second blog on attacking the SAP PASSCODE has click here.
For the third blog on attacking the SAP PWDSALTEDHASH has click here.
Questions that will be answered in this blog are:
How does the rule based attack work?
How to use the rules on found passwords?
Where to find good rule books?
The rule based attack
The dictionary rule book attack is using the dictionary as input and then applies rules to the dictionary to generate a new password candidate.
Example words we will use are Password and Welcome.
Examples of apply some rules:
Replace a with @ will give P@ssword
Replace o with 0 will give Passw0rd and Welc0me
Replace s with $ will give Pa$$word
Replace l with ! will give We!come
All rules above combined will give P@$$w0rd and We!c0me
For full list of possible rule syntax see Hashcat site on rule-based attack.
Suppose we have guessed one correct password for one user. He made the password Welcome1!.
Now we will construct some rules:
Replace e with 3, rule will be se3
Replace l with 1 and l with !, rules will be sl1 and sl!
What has happened here? Why is this found now, and not before with the se3 rule, which should substitute the e with 3? Pretty simple: replace e with 3 in word Welcome1! will give W3lcom31!. So it replaces all and not first one. This is there background of having many rules.
Huge rulesets
With the Hashcat download you get a special directory called rules. Here there are some big rulesets available.
The nicest one is the RockYou list of rules. This is constructed based on the RockYou password list hacked in 2009 where 32 million passwords leaked. Based on English dictionary somebody has constructed the rules to come to most of these passwords.
Effectiveness of the attack
The effectiveness of the rule based attack is quite high. If you have found 1 password, you just run the complete ruleset of one of the huge lists to find multiple variations. People are not so inventive and creative. You will be surprised on the amount of password variations you find on the following words:
Welcome
Summer
Winter
Password
Apple
Android
Google
Hackers don’t start with the full dictionary. They start with the top 1000 words and apply many rules to them. From the passwords found they will start to derive patterns of the users. Any new password is processed through many new rules to generate candidates with higher potential.
The name and or abbreviation of a company is word number 1 to add to the favorite word list.
Further optimization of the attack speed
For optimizing the attack speed, read the fifth blog on SAP password hash hacking here.
Prevention measure 1: frequent change and large change per time
Many companies have implemented a more faster cycle of password changes. In the past once per year was common. Nowadays 60 to 90 days is more common practice. Set this in profile parameter: login/password_expiration_time.
More important is to make a larger change per time the password changes. This is to avoid the rule-attacks explained above to become very effective. How many people just simply change and increase single digit in password? Or increase the special with the next one on the keyboard. Set the profile parameter login/min_password_diff to sufficiently high value of 3 or more.
Prevention measure 2: length
Explain to your users that length is more important than complexity by using this famous explanation:
Prevention measure 3: stronger hashes
Stronger hashes simply take more time to crack. To set stronger hashes, read this dedicated blog.
Next blog on password hacking
The fifth blog on password hacking is about optimizing the attack speed. Read on in the blog. And the blog on extended word lists.
For some batch jobs you want to have the execution done and don’t want to fill up your system with large spool files of this execution. This blog will explain to setup printer NULL to have a batch job suppress the output generation.
Questions that that will be answered in this blog are:
How do I setup printer NULL?
How to test the setup of printer NULL?
Where to find more background information on printer NULL?
Setup of printer NULL
Start transaction SPAD to define a new printer. Now create printer call NULL (with long and short name both NULL):
Select a simple windows driver. Fill the other mandatory fields. Add the message description clearly that the output will be lost.
Save the printer definition.
Testing the NULL printer
From the blog explaining the technical clean up we will take program RSWWHIDE. This program generates huge amount of output (per deleted item 3 to 10 lines). We will run the program twice in test mode: once with printer NULL and once with printer LP01 (default printer). Selection of printer NULL is same as with any printer:
Result in SM37:
The first run with printer NULL has suppressed the generation of the spool file.
This blog will explain how to scan ABAP coding in search of a specific keyword or string. Many times older or badly written programs contain hard code logic like system ID’s, plant codes, movement types, order types etc. When a larger business change happens you need to find these codes in your ABAP code and act on them. This blog will explain how to do this search.
Questions that will be answered are:
How does the scan program work?
How to search for certain strings?
How to search for words in the comments?
ABAP search tool
You can start the ABAP search tool with transaction code CODE_SCANNER:
REPORT zscantest2.DATA zt001w TYPE t001w.SELECT SINGLE werks FROM t001w INTO zt001w.IF zt001w-werks EQ 'DE01'.WRITE: 'German plant'.ELSEIF zt001w-werks EQ 'US01'.* USA plantWRITE: 'US plant'.ELSE.WRITE: 'diffferent plant'.ENDIF.
If we now start a search with the word ‘S4H’ we get this result:
A hard coded SID.
If we search with ‘US01’ we get this result:
A hard coded plant.
If we search with ‘USA’ we get this result:
The word we were looking for is in the comment lines.
Search alternative program RS_ABAP_SOURCE_SCAN
In SAP note 2764076 – CODE_SCANNER not working properly, SAP explains that CODE_SCANNER might not always work for every release. They offer alternative program RS_ABAP_SOURCE_SCAN (there is no transaction code for this program, so start via SE38):
This blog will analyze some of the tables behind the SAP user license measurement.
Warning: the list of tables below is not complete. Do not base any assumptions on the content of these tables in your system. In updates and newer versions all content can change. The tables and the text in blog is to give you insight into the process. In any contract SAP will claim the right for inspection of actual usage of your system versus the license rights in your contract.
Questions that will be answered are:
How do I know which objects are measured?
How are objects measured?
How can I find actual measured objects?
The general user measurement principles are explained in the blog on USMM.
The tables behind license measurement
The best table to start with is the TUAPP table: measurement of applications.
Example is given below:
Here you can see that Advanced ATP is measured via call function module. In SE37 you can lookup the function module and see inside the code what exactly is measured:
The other entry in TUAPP we will take as example is Procurement Orders. Its application ID is 5000 and does not measure via function module.
First we get the application to unit and unit name from table TUAPP_UNT (units themselves are defined in table TUUNT):
Now we see procurement is counting Inquiry, Purchase order, Contract, Scheduling Agreement and Others.
The actual values read by the measurement for the application counters are stored in table TUCNT:
The tables behind the AC checks
The AC (anti cheating) modules use bit different tables.
Table TUL_AC_UNIT is to denote the table to count on:
Here you see the main procurement table EKKO has ID number 5018.
In table TUL_ACTTC you can lookup this value:
This data will be used in dynamic SQL statement that will list the user name (ERNAM) who did the create or change and uses AEDAT (last change or creation date) for table EKKO to count for check 5018.
Be careful with the interface users. If an external system posts data into SAP system with a single background user, but it is clear that in the source system multiple real users doing the actions, SAP might want to charge you for 'indirect use'.
For live support of an SAP system you typically will have 2 types of support users:
Users for SAP themselves to logon to your system and provide support to you
Fire-call users with elevated authorizations to solve time critical incidents
Both type of users have no direct business goal, but have only support usage. You can mark them as type 91 Test user, as long as you have a clear naming convention for these users and a general rule that they are locked unless they are needed.
User deletion as regular activity
The user measurement program (both USMM and USMM2) checks for deletion of users in the last three months. To avoid discussions on user deletion it is best practice to delete monthly, or bi-monthly, all persons which have left your company.
End validity date
Users who don’t have a current validity date are not counted in the user measurement program. You might want to schedule program RSUSR_LOCK_USERS in a regular batch job to end the validity of users that did not log on for long time automatically. See this blog for more details.
Multiple logon
SAP does measure how many times a user has a double, triple, etc logon. The results are stored in table USR41_MLD. SAP might argue that the same user is used by multiple persons. You can use the contents of table USR41_MLD to prove if this was a mistake only. If the are too many multiple logons you might need to go back to the business to change their behavior.
You can also forbid the multiple logons at system level. SAP system parameter login/disable_multi_gui_login can be set in RZ11 to forbid multiple logons. For some users (like DDIC) you do want to keep multiple logons. These users must be set into system parameter login/multi_login_users=username1,username2,username3,etc.
Proper consolidation
Use the SLAW or SLAW2 tool to execute a proper consolidation of your measured users. This process will de-duplicate your counted users.
License validation program
Read this dedicated blog to know more about license vailidation program RSUVM080.
LUI License utilization information
The LUI (license utilization information) tool is an online SAP tool that has all the information on your on premise and cloud licenses information combined. For cloud the usage is automatically visible. For on premise systems you can upload the usage via the SLAW files. This can give you insights into under-consumption and over-consumption of licenses. Read more in this blog.
Check for bug fix notes in your advantage
SAP might give you a list of OSS notes to apply in your system before the measurement. These notes normally benefit SAP. You can also check for OSS notes that benefit you.
