Redazione RHC : 10 July 2025 07:48
Recently, the popular underground forum exploit.in, currently closed and accessible by invitation only, has been offering exploits for a 0day vulnerability affecting the well-known WinRAR and WinZIP programs. The ad, posted by user zeroplayer, offers these exploits for between $80,000 and $100,000.
Specify that this is not a simple 1-day (i.e., an exploit for a vulnerability already known as CVE-2025-6218), but an unknown and not yet patched bug.
Exploits are tools or portions of code that allow you to exploit software vulnerabilities to achieve unintended behavior, such as executing malicious code, stealing data, or gaining complete control of a system.
When we talk about 0day, we mean vulnerabilities that are not yet known to the software manufacturer and for which there are no patches: for this very reason, they are particularly valuable on the black market and incredibly dangerous.
WinZIP and WinRAR are the most widely used software in the world for managing compressed archives such as ZIP and RAR files. A RCE (Remote Code Execution) vulnerability in this type of program allows an attacker to execute malicious code simply by tricking the victim into opening or viewing a compromised archive.
One possible attack scenario involves the use of phishing emails, in which the user receives a seemingly harmless ZIP or RAR attachment. Just one click is enough to activate the exploit and completely compromise the system, installing malware, ransomware or backdoors for remote control.
Closed forums like exploit.in serve as marketplaces for buying and selling vulnerabilities, malware, stolen data, and other tools used in cybercrime. Users selling exploits, as in the case of zeroplayer, often offer guarantees of reliability through internal services called Garant, which act as intermediaries to prevent scams between criminals.
The user zeroplayer, who posted the ads, appears to be a new profile and does not yet have an established reputation. Registered on the exploit.in forum only on June 30, 2025, he has only 3 posts and has not yet completed any transactions certified through the platform’s internal Garant system, which typically serves to reduce the risk of scams between sellers and buyers.
Although he paid to register, a common practice in more closed underground forums to filter out fake and inactive accounts, this alone isn’t enough to define him as trustworthy in the eyes of the community. Such a recent account could point to two opposing scenarios: on the one hand, a vendor who genuinely possesses a highly valuable exploit and chooses to open a new profile for the sake of anonymity; on the other, a fraud attempt to capitalize on fear surrounding a critical and still-unknown vulnerability. The lack of feedback and past activity makes it difficult to distinguish between the two possibilities, but it underscores how complex it is—even in cybercrime circles—to trust the exploit without concrete proof of its existence and effectiveness.
The sale of a 0-day exploit for WinRAR poses a serious threat, given the software’s global reach. This is a further reminder of the importance of keeping your programs up to date, using reliable security tools, and paying close attention to suspicious emails, especially if they contain compressed attachments.
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