Hackers have began to use a vital distant code execution vulnerability in Wing FTP Server simply at some point 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 very best severity rating. It’s a mixture of a null byte and Lua code injection that permits distant a unauthenticated attacker to execute code with the very 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, safety researcher Julien Ahrens revealed 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 may bypass authentication checks and allow Lua code injection into session information.
When these information are subsequently executed by the server, it’s doable 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 consumer passwords by way of a crafted URL if the consumer submits a login kind, as a consequence of 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 way more harmful
- CVE-2025-47813 – supplying an overlong UID cookie reveals file system paths
All the failings impression Wing FTP variations 7.4.3 and earlier. The seller fastened 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 beneath how hackers may leverage it in assaults:
Huntress researchers discovered that on July 1st, a day after technical particulars for CVE-2025-47812 appeared, at the very least one attacker exploited the vulnerability at one among their clients.
The attacker despatched malformed login requests with null-byte-injected usernames, concentrating on ‘loginok.html.’ These inputs created malicious session .lua information that injected Lua code into the server.
The injected code was designed to hex-decode a payload and execute it by way of 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 had been for reconnaissance, acquiring persistence within the setting, and information exfiltration utilizing the cURL device and webhook endpoint.
The hacker failed the assault “possibly as a consequence of 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 vital Wing FTP Server vulnerability.
Even when Huntress noticed failed assaults at their clients, hackers are prone to scan for reachable Wing FTP situations and attempt to benefit from weak servers.
Firms are strongly suggested to improve to model 7.4.4 of the product as quickly as doable.
If switching to a more moderen, safe model shouldn’t be doable, the researchers’ advice is to disable or prohibit HTTP/HTTPs entry to the Wing FTP net portal, disable nameless logins, and monitor the session listing for suspicious additions.
Whereas cloud assaults could also be rising extra refined, attackers nonetheless succeed with surprisingly easy strategies.
Drawing from Wiz’s detections throughout hundreds of organizations, this report reveals 8 key strategies utilized by cloud-fluent menace actors.
