Attackers are reportedly targeting an NGINX/php-fpm vulnerability to infect users of the NextCloud file sync and share service with a recently discovered ransomware called NextCry.
Infecting a NextCloud instance is doubly damaging to victims because the affected service begins replacing files stored on their synced-up machines with the newly encrypted versions.
In a Nov. 15 report, BleepingComputer describes the NextCry as a "Python script compiled in a Linux ELF binary using pyInstaller." It encrypts files with an AES algorithm, and has an RSA2048 public key embedded in the malware code. Researcher Michael Gillespie also noted that the file names are encoded with Base 64, as are affected files after they are initially encrypted.
For now, there is no known way to decrypt this malware and, as of at least Nov. 15, NextCry had zero detections on VirusTotal.
A sample examined by BleepingComputer delivered a ransom note asking for 0.025 bitcoin, which today amounts to just over $200. "When executed the ransomware will first find the victim's Nextcloud files share and sync data directory by reading the service's config.php file," says the report. "It will then delete some folders that could be used to restore files and then encrypts all the files in the data directory."
Per BleepingComputer, NextCloud believes the NextCry attackers are infecting a small number of victims via CVE-2019-11043, a remote code execution in the NGINX web server and php-fpm (FastCGI Process Manager) that was patched late last October. Users are encouraged to update their PHP packages and NGINX configurations.
(BleepingComputer credited several of its own forum members for contributing to its discoveries surrounding NextCry.)