Hackers are exploiting crucial RCE flaw in Wing FTP Server

Hackers have began to take advantage of a crucial distant code execution vulnerability in Wing FTP Server simply in the future after technical particulars on the flaw turned public.

The noticed assault ran a number of enumeration and reconnaissance instructions adopted by establishing persistence by creating new customers.

The exploited Wing FTP Server vulnerability is tracked as CVE-2025-47812 and obtained the best severity rating. It’s a mixture of a null byte and Lua code injection that enables distant a unauthenticated attacker to execute code with the best privileges on the system (root/SYSTEM).

Wing FTP Server is a robust resolution for managing safe file transfers that may execute Lua scripts, which is extensively utilized in enterprise and SMB environments.

On June 30, security researcher Julien Ahrens printed a technical write-up for CVE-2025-47812, explaining that the flaw stems from unsafe dealing with of null-terminated strings in C++ and improper enter sanitization in Lua.

The researcher demonstrated how a null byte within the username discipline might bypass authentication checks and allow Lua code injection into session recordsdata.

When these recordsdata are subsequently executed by the server, it’s attainable to attain arbitrary code execution as root/SYSTEM.

Together with CVE-2025-47812, the researcher offered one other three flaws in Wing FTP:

• CVE-2025-27889 – permits exfiltrating person passwords through a crafted URL if the person submits a login type, resulting from unsafe inclusion of the password in a JavaScript variable (location)
• CVE-2025-47811 – Wing FTP runs as root/SYSTEM by default, with no sandboxing or privilege drop, making RCEs much more harmful
• CVE-2025-47813 – supplying an overlong UID cookie reveals file system paths

All the failings affect Wing FTP variations 7.4.3 and earlier. The seller mounted the problems by releasing model 7.4.4 on Might 14, 2025, apart from CVE-2025-47811, which was deemed unimportant.

Risk researchers at managed cybersecurity platform Huntress created a proof-of-concept exploit for CVE-2025-47812 and present within the video under how hackers might leverage it in assaults:

Huntress researchers discovered that on July 1st, a day after technical particulars for CVE-2025-47812 appeared, at the least one attacker exploited the vulnerability at one among their prospects.

The attacker despatched malformed login requests with null-byte-injected usernames, focusing on ‘loginok.html.’ These inputs created malicious session .lua recordsdata that injected Lua code into the server.

The injected code was designed to hex-decode a payload and execute it through cmd.exe, utilizing certutil to obtain malware from a distant location and execute it.

Huntress says that the identical Wing FTP occasion was focused by 5 distinct IP addresses inside a short while body, probably indicating mass-scanning and exploitation makes an attempt by a number of menace actors.

The instructions noticed in these makes an attempt have been for reconnaissance, acquiring persistence within the atmosphere, and knowledge exfiltration utilizing the cURL device and webhook endpoint.

The hacker failed the assault “perhaps resulting from their unfamiliarity with them, or as a result of Microsoft Defender stopped a part of their assault,” Huntress says. However, the researchers noticed clear exploitation of the crucial Wing FTP Server vulnerability.

Even when Huntress noticed failed assaults at their prospects, hackers are prone to scan for reachable Wing FTP situations and attempt to reap the benefits of susceptible servers.

Corporations are strongly suggested to improve to model 7.4.4 of the product as quickly as attainable.

If switching to a more recent, safe model will not be attainable, the researchers’ advice is to disable or prohibit HTTP/HTTPs entry to the Wing FTP internet portal, disable nameless logins, and monitor the session listing for suspicious additions.