CVE-2023-40044 — Progress WS_FTP Server Deserialization of Untrusted Data Vulnerability

In WS_FTP Server versions prior to 8.7.4 and 8.8.2, a pre-authenticated attacker could leverage a .NET deserialization vulnerability in the Ad Hoc Transfer module to execute remote commands on the underlying WS_FTP Server operating system.

01What is this vulnerability?

In WS_FTP Server versions prior to 8.7.4 and 8.8.2, a pre-authenticated attacker could leverage a .NET deserialization vulnerability in the Ad Hoc Transfer module to execute remote commands on the underlying WS_FTP Server operating system.

02Affected products

Vendor	Product	Versions
Progress Software Corporation	WS_FTP Server	8.8.0, 8.7.0

03Active exploitation status

Yes — actively exploited. Added to the CISA KEV catalog on 2023-10-05. Ransomware use: Known.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Open the Sigma generator with a pre-filled prompt for this CVE to draft a starting detection in your stack of choice:

Open in Sigma generator →

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2023-09-27T14:48:08.190Z
• Last modified: 2025-10-21T23:05:36.645Z
• Added to CISA KEV: 2023-10-05
• BOD 22-01 due: 2023-10-26

09References

• www.progress.com — https://www.progress.com/ws_ftp
• community.progress.com — https://community.progress.com/s/article/WS-FTP-Server-Critical-Vulnerability-Se…
• www.theregister.com — https://www.theregister.com/2023/10/02/ws_ftp_update/
• www.rapid7.com — https://www.rapid7.com/blog/post/2023/09/29/etr-critical-vulnerabilities-in-ws_f…
• attackerkb.com — https://attackerkb.com/topics/bn32f9sNax/cve-2023-40044
• censys.com — https://censys.com/cve-2023-40044/
• www.assetnote.io — https://www.assetnote.io/resources/research/rce-in-progress-ws-ftp-ad-hoc-via-ii…
• packetstormsecurity.com — http://packetstormsecurity.com/files/174917/Progress-Software-WS_FTP-Unauthentic…