IRONSMITHINTEL
CRITICALCVSS10.0
|
Actively Exploited
|CISA KEV|CVE-2023-40044|Auth: none — unauthenticated|Reboot: required|Manual only

Progress WS_FTP Server Deserialization of Untrusted Data Vulnerability

Progress WS_FTP Server contains a deserialization of untrusted data vulnerability in the Ad Hoc Transfer module that allows an authenticated attacker to execute remote commands on the underlying operating system.

Published Sep 27, 2023 · Updated May 16, 2026
Why patchRisk explained in plain English
Worst-case scenarioIf unpatched

A remote attacker, without authentication, can achieve full data confidentiality loss, arbitrary modification of data, complete denial of service or system unavailability. CISA has confirmed use of this vulnerability in known ransomware campaigns — treat as high priority for remediation. Federal agencies are required to remediate by 2023-10-26 under CISA BOD 22-01.

How the attack worksNo clicks needed

This is a Deserialization of Untrusted Data (CWE-502) vulnerability in Progress WS_FTP Server. 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. Exploitation requires remote network access, low attack complexity, no authentication required, and no user interaction required.

📧

Phishing link

🖼

Malicious file

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Server compromised

Am I affected?Quick check

Probably yes if any of these apply:

IT Security
Running ws ftp server: v < 8.7.4, 8.8 ≤ v < 8.8.2
Real-world incidentsWhat we've seen

Used in known ransomware campaigns. Threat-research write-up: http://packetstormsecurity.com/files/174917/Progress-Software-WS_FTP-Unauthenticated-Remote-Code-Execution.html

How to patch

Manual remediation steps

Apply the Vendor Patch

This vulnerability is in the CISA Known Exploited Vulnerabilities catalog — apply the vendor's security update as soon as possible.

CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

References

    1
    Vendor advisory: https://community.progress.com/s/article/WS-FTP-Server-Critical-Vulnerability-September-2023
    1
    NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2023-40044
    1
    CISA KEV: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-40044
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