Advisory

On 08.09.2020 a security relevant correction has been released by SAP SE. The manufacturer resolves an issue within SAP Marketing.

SAP Note 2961991 addresses "[CVE-2020-6320] Improper Access Control in SAP Marketing (Mobile Channel Servlet)" to prevent missing authorization check with a hot news risk for exploitation.

A workaround does exist, according to SAP Security Advisory team. It is advisable to implement the correction as part of maintenance, the team suggests.

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 detect code vulnerabilities before they are implemented in production.

Risk specification

The servlet reference implementation provided for the Mobile Channel Servlet in SAP Marketing allows an authenticated attacker to invoke certain functions that are restricted. The components exist within the technical architecture until 2017 and interact as a connector between customers' mobile applications and the SAP Cloud Platform (SCP).

Solution

Update the servlet to the new version. Thereafter the implementation will block unwanted URLs via web.xml. Additionally, the payload of URI requests using /$batch is scanned for its validity. Unfortunately, we are not aware whether customers have the ability to check the version of the servlet in use.  And the good news, a workaround exists, too! This was suggested by the SAP security experts: "Disable the SAP Cloud Platform Servlet Used by the SAP Marketing Mobile SDK as described in Note 2962970."

The advisory is valid for

 

Disclaimer

ABEX takes the security of SAP products very seriously. We very much encourage the responsible disclosure of security vulnerabilities. If you have detected a vulnerability in one of the SAP software products – either in the latest or in a former product version follow the guidelines and processes in accordance with the SAP portal page “Report a Security Vulnerability to SAP”.

The advisories found within the ABEX security advisory are generated and continuously enriched by ABEX and affiliated security consultants, partners, customers of the SecurityBridge security suite, SAP support, and advisory groups.

There is no disclosure of zero-day vulnerabilities. In such case, the platform only provides details on which version or signature updates are available within the SecurityBridge platform in order to monitor or measure the vulnerability

In accordance with SAP guidelines, ABEX only discloses issues where the fixing security note has been released at least three months ago. The vulnerability platform makes no references to available exploits or Proof of Concepts (PoC). Advisories and vulnerabilities will always mention the fixing security note or hints to the corresponding SAP documentation.

 

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