A note with CVSS 4.1 for component CA-WUI-UI was released by SAP on 09.02.2021. The correction/advisory 2994289 was described with "Reverse Tabnabbing vulnerability within SAP CRM WebClient UI" and affects the system type ABAP.
A workaround does not exist, according to SAP Security Advisory team. It is advisable to implement the correction as monthly patch process.
The vulnerability addressed is reverse tabnabbing within ABAP.
Missing authority checks are still the most common security defect related to authorizations in custom code.
Since SAP uses an explicit authorization model, an authority checks must be coded in order to be executed. If an
explicit check is not coded, all users have access.
This type of vulnerability not only exists in SAP standard it also exists in customer coding. Check your custom
developments for vulnerabilities that pose a risk to your systems. SecurityBridge helps
vulnerabilities before they are implemented in production.
Reverse tabnabbing is an attack where a page linked from the target page is able to rewrite that page, for example
to replace it with a phishing site. The following figure shows a brief illustration:
While the user was originally on the correct page there is a high risk they will not notice that it has been changed to a phishing site.
Risk specificationSAP CRM WebClient UI allows an unauthenticated remote attacker to redirect users to a malicious site due to insufficient reverse tabnabbing URL validation.
The affected BCP application has been altered to no longer allow this type of attack
The advisory 2994289 describes a problem within an ABAP based systems of a specific version. Affected versions are described below. ABAP software is deployed in various software components and is widely used within the SAP product portfolio.
SAP NetWeaver Application Server (formally known as SAP Web Application Server) is a building block of SAP NetWeaver. It is the foundation for most software products developed by SAP SE. SAP NetWeaver systems exist with Java and/or ABAP stacks. The advisory could be relevant for single and dual-stack ABAP installations.
The advisory is valid for
- S4FND 102 3
- S4FND 103 3
- S4FND 104 3
- S4FND 105 2
- WEBCUIF 700
- WEBCUIF 701
- WEBCUIF 730
- WEBCUIF 731 3
- WEBCUIF 746 3
- WEBCUIF 747 3
- WEBCUIF 748 3
- WEBCUIF 800 3
- WEBCUIF 801 3
- 4.7 [CVE-2021-21478] Reverse Tabnabbing vulnerability in SAP NetWeaver Application Server ABAP (Applications based on Web Dynpro ABAP)
- 4.7 Reverse Tabnabbing vulnerability within SAP NetWeaver Application Server ABAP (Applications based on SAP GUI for HTML)
- 4.7 [CVE-2021-21491] Reverse TabNabbing vulnerability in SAP NetWeaver Application Server Java (Applications based on Web Dynpro Java)
- 4.7 Reverse TabNabbing vulnerability in SAP NetWeaver Application Server Java (Applications based on HTMLB for Java)
- 4.7 Reverse tabnabbing issue in Unified Rendering based frameworks in NetWeaver Application Server Java