Understanding the Importance of the &NC& Table Group in SAP Security and how to safeguard within SAP Authorization Management

Effective SAP authorization management is essential for maintaining the security and integrity of enterprise resource planning (ERP) systems. It ensures that users have appropriate access permissions without compromising sensitive data. Among the crucial components of SAP security, the &NC& table group plays a pivotal role. In this blog, we’ll explore why the &NC& table group is safety-critical and how we can protect sensitive data within this context. Table groups serve as a fundamental organizational structure within SAP systems, enabling administrators to efficiently manage access to related tables. These groups facilitate the application of access controls, ensuring that users interact only with authorized data. One significant table group within SAP is the &NC& group, which stands for “not classified.” This designation indicates that tables in this group have not been assigned to a specific authorization category. Essentially, tables in the &NC& group lack explicit access controls, making them potentially vulnerable to unauthorized access.

The safety-critical nature of the &NC& table group stems from its ability to expose sensitive data if left unsecured as commonly a high number of tables are not classified in SAP systems. Access to the &NC& group grants users privileges across all tables within this category, potentially compromising confidential or proprietary information. Unauthorized users could exploit this broad access to retrieve sensitive data or manipulate system records.

While SAP standard transactions typically access data through front-end applications, users can also directly interact with tables using generic table transactions like SE16, SE16N, SE17, SM30, or SM31. These transactions enable users to view or modify tables, bypassing some built-in authorization checks. For example, consider the transaction FK03 used to display supplier data. While FK03 enforces authorization checks based on activity, application, and company code, accessing the same data through SE16 or SM30 circumvents these checks, allowing unrestricted access to supplier data.

Role administrators can use authorization objects like S_TABU_DIS or S_TABU_NAM to restrict the access. Previously, S_TABU_DIS was checked first for authorization, but starting with SAP_BASIS 7.50, the order is inverted, with S_TABU_NAM taking precedence. For client-independent tables, the system also verifies S_TABU_CLI to authorize data modifications (SAP Note 3077347). Administrators can adjust authorization groups for tables using transactions like STDDAT or SE54, specifying the new authorization group to control access effectively. Changing the authorization group from “&NC&” to a suitable one requires a data concept and therefore might be a more complex solution.

Figure 1: Change authorizations group with STTDAT

Safeguarding table group &NC& using the Xiting Authorizations Management Suite

When there are no alternatives but to grant direct access to tables via SE16* or SM30, using a parameter transaction can be a solution to mitigate risks. The Xiting Authorization Management Suite (XAMS) provides a mass creation tool for parameter transactions, as detailed in the blog by one of our SAP Security consultants, Annika Braun:

How to detect roles with &NC& table groups via Role Profiler

To further reduce risks associated with S_TABU_DIS and &NC&, transparency in identifying roles containing S_TABU_DIS with &NC& and managing the assignment of S_TABU_NAM before S_TABU_DIS is crucial.

XAMS offers a solution for this challenge through its Role Profiler tool, which identifies issues in existing roles and authorizations. Specifically, it detects critical authorizations like S_TABU_DIS with &NC& using the XAMS Critical Authorization Framework (CRAF). Additionally, it provides an SU24 optimization tool for parameter transactions (both SAP standard and custom transactions). The importance of well maintained SU24 proposals is detailed in following blog.

Given the critical nature of S_TABU_DIS and &NC&, the XAMS ruleset “CRAF” includes a check ID for this authorization. By specifying selection criteria (e.g., Z-namespace), you can generate a list of roles containing S_TABU_DIS with “&NC&”, highlighted with a red dot for easy identification.

Figure 2: Role Profiler CRAF

An effective approach is to utilize parameter transactions instead of granting direct SE16/SM30 access, as previously mentioned. This strategy prevents users from accessing the main screens and mitigates the risk of unauthorized access to sensitive data. But how can you easily identify the usage of these transactions?

Efficient usage analysis of generic table transactions via XAMS Role Profiler

With the Role Profiler tool, you can thoroughly scan roles to gain a clear understanding of your current access model. This includes assessing how many users have access to transactions such as SE11, SE16, SE16N, SE17, SM30, and SM31 by leveraging the “Generic Table Access for Users” report.

This specialized report checks all users within scope for these critical transactions and verifies if they are appropriately authorized. It also tracks whether users have actively utilized these transactions within a specified time frame, using data from the security audit log and ST03N.

Furthermore, the report provides insights into which tables have been accessed by users via these transactions and whether this access was done remotely or locally. Additionally, the report checks if the access was authorized via parameter transactions, ensuring that users are properly authorized based on their assigned roles and SU24 data:

Figure 3: Generic table access in the XAMS Role Profiler

This provides a crucial overview for restricting the allocation of specific transactions and, when necessary, replacing them with parameter transactions. As outlined in Annika Braun’s blog post, parameter transactions can be efficiently created in bulk using the Role Replicator tool.

Easy SU24 optimization for S_TABU* objects within XAMS Role Profiler

To maintain SU24 efficiently for parameter transactions, the Role Profiler optimization reports for tables offer a clear overview of the required SU24 proposal and table values that need to be maintained. The “Parameter tcodes S_TABU*” reports specifically target parameter transactions related to core transactions like SE16*, SM30, SM31, or SM34* and examine their SU24 proposals. These reports respect the constraints of the role selection filter, enabling scanning of transactions for incomplete S_TABU_* proposals that are actively in use. SU24 proposals for S_TABU* objects should either exist for the table name or the table group maintained in SU24. If these proposals are not maintained for parameter transactions, the core transaction’s proposals are used by default, which are typically not maintained and lack knowledge of the table or view name. The “Flag” field indicates whether the object’s proposals are incomplete or incorrect. For instance, if S_TABU_CLI exists but the table is client-dependent, a warning is displayed. Updating SU24 with values is made easy by double-clicking on the update icon, allowing you to overwrite or append values and assign them to a transport request.

For example, consider transaction ZBIZTCODE, based on SE16 and assigned to a specific role, accessing table ZBIZROLES within table group &NC&. As SU24 proposals in S_TABU_DIS and S_TABU_NAM are missing, you can e.g. update S_TABU_NAM by double-clicking on the blue arrow:

Figure 4: Role Profiler Parameter tcodes S_TABU*


In conclusion, effective SAP authorization management is crucial for maintaining robust data security. By leveraging parameter transactions over direct table access, and prioritizing transaction-based access controls and regularly maintaining SU24 settings, organizations can significantly enhance their security posture. XAMS streamlines authorization processes, reducing the risk of unauthorized access and data breaches. Through features like the Role Profiler, administrators can gain insights into user access patterns and make informed decisions to bolster security.

If you’re eager to delve deeper into these strategies, consider requesting a personalized webinar. Our webinars offer practical demonstrations and hands-on experience with the technology. Additionally, explore customized training sessions or inquire about implementation consulting tailored to your company’s unique needs.

We’re committed to supporting your organization’s success by providing expert advice and assistance in implementing best practices for SAP security.

Carmen Cristurean

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