CVE-2017-12796

The Reporting Compatibility Add On before 2.0.4 for OpenMRS, as distributed in OpenMRS Reference Application before 2.6.1, does not authenticate users when deserializing XML input into ReportSchema objects. The result is that remote unauthenticated users are able to execute operating system commands by crafting malicious XML payloads, as demonstrated by a single admin/reports/reportSchemaXml.form request.

Weakness

The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

Affected Software

Potential Mitigations

• Make fields transient to protect them from deserialization.
• An attempt to serialize and then deserialize a class containing transient fields will result in NULLs where the transient data should be. This is an excellent way to prevent time, environment-based, or sensitive variables from being carried over and used improperly.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/586.html

References

• https://isears.github.io/jekyll/update/2017/10/21/openmrs-rce.html
• https://talk.openmrs.org/t/critical-security-advisory-2017-09-12/13291
• https://wiki.openmrs.org/display/RES/Release+Notes+2.6.1
• https://isears.github.io/jekyll/update/2017/10/21/openmrs-rce.html
• https://talk.openmrs.org/t/critical-security-advisory-2017-09-12/13291
• https://wiki.openmrs.org/display/RES/Release+Notes+2.6.1