Online imageboard 4chan experienced a substantial security breach in mid-April 2025, with individuals linked to the rival forum Soyjak.party claiming responsibility. Attackers reportedly leveraged severe vulnerabilities in outdated server software to gain administrative privileges, leak moderator credentials including personal emails and passwords, and temporarily reinstate the previously deleted /QA/ discussion board.
The incident throws a harsh light on the platform’s aging technical infrastructure, with the attacker allegedly using the handle “Chud” claiming on Soyjak.party to have maintained access for over a year before executing “operation soyclipse” around April 14th.
Exploiting Decade-Old Vulnerabilities
Multiple reports and analyses suggest the attackers employed at least two distinct methods exploiting decade-old software. One significant vector, initially detailed in Know Your Meme’s reporting and user analysis, involved manipulating the PDF upload feature available on boards such as /sci/ and /tg/.
According to these accounts, 4chan’s system failed to properly validate uploaded file types, allowing attackers to submit malicious PostScript files disguised with a .pdf extension. PostScript is a page description language known for its programming capabilities. These files were then allegedly processed by a Ghostscript interpreter version from 2012 to create image thumbnails.
Ghostscript is a common tool for handling PostScript and PDF files. Attackers apparently leveraged known, critical vulnerabilities in this antiquated version, possibly using a “translation boundary break” technique, to execute commands directly on the server, achieving shell access. These specific Ghostscript flaws have long been addressed in modern, patched versions.
A second reported vulnerability pathway involved 4chan’s core PHP codebase. Analysis of leaked source code, including the extensive yotsuba.php script responsible for posting and moderation, indicated the use of outdated PHP versions alongside deprecated MySQL functions.
So 4chan very likely got hacked because they were running on an extremely out of date version of PHP that has a lot of vulnerabilities and exploits and are using deprecated function to interact with there MySQL database.
— Yushe (@_yushe) April 15, 2025
Web security 101: Keep your code and software up to date. pic.twitter.com/JFDOsbr5rt
Further compounding the issue, evidence emerged showing at least one server running FreeBSD 10.1, an operating system version initially released in late 2014 that reached its official end-of-life for security support in 2016. Running critical web infrastructure on unpatched, unsupported operating systems and decade-old components presents obvious and substantial security risks, leaving systems exposed to well-documented exploits.
Systemic Issues and Compromised Data
This reliance on obsolete technology reflects a pattern of neglected maintenance and technical debt accumulation, potentially worsening after current owner Hiroyuki Nishimura acquired the site in 2015.
The immediate fallout from this latest breach includes the exposure of sensitive data belonging to approximately 218 volunteer moderators (“janitors”). Leaked information reportedly includes email addresses, passwords, and IRC logs.
The presence of several .edu email addresses in the leak was confirmed, although initial social media rumors mentioning .gov emails have not been verified by reputable sources. Cybersecurity researcher Kevin Beaumont assessed the situation for The Register, stating it was a “pretty comprehensive [compromise] including SQL databases, source and shell access”. Corroborating the severity, an anonymous 4chan moderator apparently confirmed to TechCrunch that the leaked moderator data seemed “all real”.
Attribution and Lingering Questions
The restoration of the /qa/ board, a community banned in 2021 whose users largely formed Soyjak.party, points towards a potential retaliatory motive for the attack. The incident follows previous security issues, like a 2014 hack involving compromised moderator credentials confirmed by founder Christopher Poole.
The current breach leaves questions about the platform’s recovery capability and the potential long-term risks stemming from the exposure of moderator information and internal data, despite the alleged hacker stating user data was not a target. Following the disclosure, 4chan experienced extended downtime before slowly returning to partial service.
