The main distribution server of the open-source ProFTPD Project was compromised in an attack that enabled whoever was behind it to upload and distribute a malicious version of ProFTPD software.
The ProFTPD Project develops file transfer protocol (FTP) server software. According to the project team, the compromise occurred Nov. 28, and went undetected until Dec. 1. In addition to the main distribution server, all the mirror servers were affected as well, and any users running versions of ProFTPD that have been downloaded and compiled during the past few days should "check their systems for security compromises and install unmodified versions of ProFTPD," the team advised.
In a message to the project's mailing list on SourceForge, Project Maintainer TJ Saunders speculated the attacker or attackers used an unpatched security vulnerability in the FTP daemon to gain access to the server and then replaced the source files for ProFTPD 1.3.3c with a version containing a backdoor.
"The fact that the server acted as the main FTP site for the ProFTPD project (ftp.proftpd.org) as well as the rsync distribution server (rsync.proftpd.org) for all ProFTPD mirror servers means that anyone who downloaded ProFTPD 1.3.3c from one of the official mirrors from (Nov. 28) to (Dec. 2) will most likely be affected by the problem," he wrote.
"The backdoor introduced by the attackers allows unauthenticated users remote root access to systems which run the maliciously modified version of the ProFTPD daemon," Saunders added.
Earlier this week, reports surfaced a site belonging to the GNU Savannah project had been compromised via SQL injection, leading to a leak of encrypted account passwords.
In the case of the attack on ProFTPD, users are "strongly advised to check systems running the affected code for security compromises and compile/run a known good version of the code," Saunders wrote. "To verify the integrity of the source files, use the GPG signatures available on the FTP servers as well on the ProFTPD homepage at: http://www.proftpd.org/md5_pgp.html."