Muhstik Ransomware

The Muhstik Ransomware is a file-locking Trojan that targets and blocks the contents of QNAP-brand, network-attached storage. Users can protect these devices with appropriate password-maintenance practices, but also may restore their files with a free decryptor. Before retrieving your data by any convenient method, always check associated devices and PCs with anti-malware solutions for removing the Muhstik Ransomware, if necessary.

Trojan Attacks Man – and Man Returns the Favor

The story of a victim using an inferior password and getting a Trojan that locks all of his media is too commonplace, but, sometimes, the ending goes a little differently. The Muhstik Ransomware, an independent Trojan that targets QNAP NAS – similarly to QNAPCrypt – follows all of these traditional steps in its campaign. Unusually, though, the consequences didn't stop there, as one victim returned the favor with interest.

Tobias Frömel, a software developer from Germany, is one of the multiple victims who paid the ransom for unlocking the contents of his storage device. However, he further analyzed the sample of the Muhstik Ransomware, traced its communications back to a key database-storing server, and acquired the contents. Then, he leaked the cryptographic unlocking solutions to the public and provided a free decryptor tool, as well. This event places the Muhstik Ransomware in the same position as the old version of the STOP Ransomware, a family whose exposed keys led to victims having a free recovery option, temporarily.

Many of the Muhstik Ransomware's traits, as a Trojan, aren't nearly as exceptional. It appends 'muhstik' extensions onto the content that it locks, doesn't target backup storage that's of a no-QNAP brand, and doesn't target PCs or non-NAS hardware. While malware experts note that it doesn't seem capable of self-distribution, the criminals operating it will search for available devices without secure passwords and run a brute-force attack for getting into them.

The Tinge of Danger Around an Otherwise-Happy Ending

While the Muhstik Ransomware offers an oddly-heartwarming tale for its current victims, the STOP Ransomware Ransomware-as-a-Service shows that Trojan encryption isn't a static obstacle. Threat actors can update their encryption algorithms, change keys, and, once again, be back in the extortion business. Victims can avail themselves of a free decryption service, while it's applicable, but may need more permanent solutions, such as a secure password and corresponding backup strategy, in the future.

The Muhstik Ransomware also is one of a select, but the group of Trojans that target network-attached storage. QNAP-specific ones like it, the QNAPCrypt, and the eCh0raix Ransomware contrast with the DecryptIomega Ransomware for Lenovo Iomega, as well as the SynoLocker Ransomware and the Chekyshka Ransomware for Synology. Users depending on NAS devices should guard them carefully and not assume that they're safer than other storage optio naturally.

Regardless of all of the above, all users should check their storage hardware and related systems with anti-malware services, in case removing the Muhstik Ransomware is required. File-locker Trojans may include additional threats beyond themselves, or coincide with theft of credentials and lateral network movement.

The Muhstik Ransomware is a happier story than most of its kind, but users shouldn't hope they'll get stuck with one of the few, crippled Trojans. Plenty more are arriving by the day, and most of them don't get their servers hacked back.