The Serv-U File Server supports site specific commands which may not be universally supported by all FTP clients. Among these is the SITE EXEC command which allows a user to execute programs and scripts remotely, if the execute permission is present on the folder where a given program / script resides. A command injection vulnerability exists in this functionality due to improper sanitization of user-supplied parameters provided to the ShellExecuteExW routine. Successful exploitation results in arbitrary command execution under the context of the file server.
- Exodus Intelligence: EIP-d3400c52
- MITRE CVE: CVE-2021-35223
- CVSSv2 Score: 9.4
- Exodus Intelligence
- Disclosed to affected vendor: May 14th, 2021
- Disclosed to public: September 24th, 2021
Readers of this advisory who are interested in receiving further details around the vulnerability, mitigations, detection guidance, and more can contact us at firstname.lastname@example.org.
Researchers who are interested in monetizing their 0Day and NDay can work with us through our Research Sponsorship Program.