Advisory

SAP takes the security of its vast product portfolio very seriously and thus releases security fixes for vulnerabilities reported by external researchers and their customers every second Tuesday of the month.

SAP Note 3053066 was released on 08.06.2021 and deals with "[CVE-2021-27635] Missing XML Validation in SAP NetWeaver AS for JAVA" within Java. We advice you to follow the instructions, to resolve external entity tunneling (xxe) with a high potential for exploitation in component BC-ESI-WS-JAV-CFG.

According to SAP Security Advisory team a workaround does not exist. It is advisable to implement the correction as part of maintenance.

Risk specification

SAP Netweaver AS for Java does not sufficiently validate uploaded XML entities allowing an authenticated user with basic privileges to inject some arbitrary XML entities leading to internal file disclosure or fully compromise availability by causing the system to crash. The attack cannot be used to change any data so that there is no compromise as to integrity.

Solution

The XML parser is now configured securely to validate submitted XML documents so that external entities are not allowed.

Affected System

SAP Netweaver Application Server Java is part of the SAP NetWeaver Application Platform. It provides the complete infrastructure for deploying and running Java applications.

The AS Java Home: SAP Netweaver Application Server Java wiki
A dedicated SAP NetWeaver 7.40 Application Server for Java Security Guide exists.

The advisory is valid for

Releated advisories

Disclaimer

SecurityBridge takes the security of SAP products very seriously. We very much encourage the responsible disclosure of security vulnerabilities. If you have detected a vulnerability concerning 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 SecurityBridge advisory are generated and continuously enriched by our Team at SecurityBridge and affiliated security consultants, partners, customers of the SecurityBridge Platform, SAP support, and advisory groups.

We do not disclose zero-day vulnerabilities unless a security patch has been made available to the public. 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, SecurityBridge only discloses issues where the fixing security note has been released. 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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Notifications

Affected system Java

CVSS 8.7

Component BC-ESI-WS-JAV-CFG

Patch Day2021-06

Released on2021/06/08

SAP Note 3053066

Workaround No

Advisory

Risk specification

Solution

Affected System

Disclaimer

_{Affected system}
Java

_CVSS
8.7

_Component
BC-ESI-WS-JAV-CFG

_{Patch Day}
2021-06

_{Released
on}
2021/06/08

_{SAP Note}
3053066

_Workaround
No