SAP NetWeaver XML External Entity (XXE)
CVE-2016-9563 is a medium-severity improper restriction of XML external entity reference vulnerability in Netweaver Application Server Java from SAP, with a CVSS 3.1 base score of 6.5 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected Netweaver Application Server Java versions: 7.50. The record does not name a fixed version, so check the vendor advisory. CISA added it to the Known Exploited Vulnerabilities catalogue on November 3, 2021, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Check which version of Netweaver Application Server Java you run against the affected versions below, and install the vendor's latest release.
- CISA's required action: Apply updates per vendor instructions.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| SAP | Netweaver Application Server Java | 7.50 | Not stated |
Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 6.5 | Medium | NVD |
| CVSS 3.1 | 6.5 | Medium | CISA (ADP) |
| CVSS 2.0 | 4.0 | Medium | NVD |
Official description
BC-BMT-BPM-DSK in SAP NetWeaver AS JAVA 7.5 allows remote authenticated users to conduct XML External Entity (XXE) attacks via the sap.com~tc~bpem~him~uwlconn~provider~web/bpemuwlconn URI, aka SAP Security Note 2296909.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Restriction of XML External Entity Reference
The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.
How developers prevent this class of flaw
- Many XML parsers and validators can be configured to disable external entity expansion.
More Improper Restriction of XML External Entity Reference vulnerabilities (CWE-611)
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2016-9563US Government Resource
Other references
- launchpad.support.sap.com/#/notes/2296909Permissions Required
Other vulnerabilities in Netweaver Application Server Java
- 7.5 High severity
- 9.1 Critical severity
- 7.5 High severity
- 8.8 High severity
- 9.8 Critical severity
- 7.5 High severity
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