CVE-2021-3199: ONLYOFFICE Docs Server Path Traversal Vulnerability

Summary

ONLYOFFICE Docs contains a path traversal vulnerability that can occur when JWT is used, via a /.. sequence in an image upload parameter and could allow for remote code execution.

Remediation

Inventory every ONLYOFFICE Docs deployment, including staging.
No fixed version appears in the public sources yet. Check the references below and the vendor directly.
Review logs from before the change for signs of exploitation.

CISA required actionApply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

References

Advisoryhttps://github.com/ONLYOFFICE/DocumentServer/blob/903fe5ab7a275bd69c3c3346af2d21cf87ebeabf/CHANGELOG.md#563
Advisoryhttps://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
Advisoryhttps://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
Advisoryhttps://nvd.nist.gov/vuln/detail/CVE-2021-3199
Referencehttps://github.com/nola-milkin/poc_exploits/blob/master/CVE-2021-3199/poc_uploadImageFile.py
Referencehttps://github.com/moehw/poc_exploits/tree/master/CVE-2021-3199/poc_uploadImageFile.py
Referencehttps://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-3199