CVE-2025-31331: SAP NetWeaver Auth Bypass Vulnerability

CVE-2025-31331 Overview

CVE-2025-31331 is an authorization bypass vulnerability in SAP NetWeaver. Authenticated attackers can invoke a specific transaction that exposes ABAP source code without the additional authorization checks the system should enforce. The flaw is classified under CWE-863: Incorrect Authorization and affects the confidentiality of protected application logic. Successful exploitation requires prior access to the ABAP system with low privileges. Integrity and availability of the target system remain unaffected, but exposed ABAP code can reveal business logic, credentials embedded in code, or additional attack surface for follow-on intrusions.

Critical Impact
Authenticated attackers can read portions of ABAP source code that should be protected, exposing sensitive business logic and enabling reconnaissance for further attacks against SAP NetWeaver environments.

Affected Products

SAP NetWeaver Application Server ABAP
SAP NetWeaver components exposing the affected ABAP transaction
Refer to SAP Note #3577131 for the authoritative list of affected releases

Discovery Timeline

2025-04-08 - CVE-2025-31331 published to NVD
2025-04-08 - SAP publishes patch guidance in SAP Note #3577131 on SAP Security Patch Day
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-31331

Vulnerability Analysis

The vulnerability lives in the authorization logic of an ABAP transaction that returns source code fragments. An authenticated user with basic ABAP system access can invoke the transaction and receive code content that would normally be gated behind additional authorization objects. Because the missing check occurs after primary logon authentication, standard role assignments do not prevent access. The exposure is limited to read access to specific ABAP code, which maps to a confidentiality-only impact.

Exposed ABAP source is high-value reconnaissance material. It can reveal function module names, database table structures, custom authorization logic, RFC-enabled endpoints, and, in poorly managed environments, hardcoded credentials or connection strings. Attackers use this material to chain further attacks against the SAP landscape.

Root Cause

The root cause is an incorrect authorization implementation [CWE-863]. The affected transaction validates that a caller is logged in but does not enforce the granular authorization object required for viewing ABAP source. The result is that any authenticated user in the ABAP client can trigger the disclosure path.

Attack Vector

The attack vector is network-based against the SAP NetWeaver ABAP server. The attacker must first authenticate to the ABAP system using valid credentials with low privileges. No user interaction is required beyond the attacker's own session. Once authenticated, the attacker executes the specific transaction identified in SAP Note #3577131 and receives ABAP code output the current role should not permit.

Because no verified public exploit code exists, exploitation is described in prose only. Consult the vendor advisory for the specific transaction code and affected components. See the SAP Security Patch Day portal for the coordinated release context.

Detection Methods for CVE-2025-31331

Indicators of Compromise

Unexpected invocations of the transaction identified in SAP Note #3577131 by users whose roles do not include ABAP development or code review duties
Security Audit Log (SM20) entries showing successful transaction starts followed by large read responses to non-developer accounts
Repeated transaction launches from a single dialog user within a short window, suggesting scripted enumeration

Detection Strategies

Enable and review the SAP Security Audit Log (SM19/SM20) for the affected transaction code and correlate against role assignments
Query the workload monitor (ST03N) for anomalous transaction execution counts among non-developer users
Forward SAP audit logs to a central SIEM and alert on the affected transaction executed by users outside expected developer or basis groups

Monitoring Recommendations

Baseline normal usage of ABAP code-display transactions across production clients and alert on deviations
Monitor authentication events for low-privilege accounts that suddenly begin invoking developer-oriented transactions
Track RFC and GUI session activity per user to identify enumeration patterns that follow disclosure of ABAP internals

How to Mitigate CVE-2025-31331

Immediate Actions Required

Apply the SAP-supplied patch referenced in SAP Note #3577131 to all affected NetWeaver ABAP systems
Inventory user accounts with access to the affected transaction and remove entitlements that are not business-justified
Review recent Security Audit Log entries for signs of the transaction being invoked by unexpected users prior to patching

Patch Information

SAP released the fix on SAP Security Patch Day. Customers should download and apply the correction detailed in SAP Note #3577131. The note identifies the exact support package levels and kernel patches required per NetWeaver release. Coordinate deployment through standard SAP transport management and validate authorization behavior in a non-production client before promotion.

Workarounds

Restrict access to the affected transaction using S_TCODE authorization objects until the patch can be deployed
Remove or lock unused dialog user accounts to reduce the population of principals that could invoke the transaction
Enforce least-privilege role design in production clients so that only development and support personnel retain code-viewing capabilities

bash

# Example: restrict transaction access via a role in PFCG
# 1. Open PFCG and edit the composite or single role granting broad access
# 2. In the Authorizations tab, locate object S_TCODE
# 3. Remove the affected transaction code listed in SAP Note #3577131
# 4. Generate the profile and re-assign the role
# 5. Verify with SU53 that the target users are denied on the transaction