Emsisoft released a free decryptor for JSWorm 4.0

Security researchers at Emsisoft have released a new decryptor tool that allows the victims of the JSWorm 4.0 ransomware to decrypt their files for free.

Thanks to the experts at Emsisoft the victims of the JSWorm 4.0 ransomware can decrypt their files for free.

Like previous versions of the malware, the JSWorm 4.0 ransomware is also written in C++ and uses a modified version of AES-256 to encrypt files.

The malicious code adds the extension “.[ID-][].JSWRM to the filenames of encrypted files. Once encrypted all data it drops the ransom note “JSWRM-DECRYPT.hta” using the following text:

"JSWRM 4.0.2 Your files are corrupted! Identificator for files: [redacted] E-mail for contact: symmetries@tutamail.com Backup e-mail for contact : symmetries0@tutanota.com Free decryption as guarantee! Before paying you can request free decryption of 3 files. Total size of files must be less than 5MB (non-archived). Files shouldn't contain valuable information (accept only txt\jpg\png). Attention! Don't try to decrypt it manually. Don't rename extension of files. Don't try to write AV companies (they can't help you). "

Emsisoft release the detailed usage guide for the decryptor that is available her e.

In May Emsisoft experts released a free Decrypter tool for the JSWorm 2.0 variant.

In July the company released other free decryptors for the LooCipher ransomware, the ZeroFucks ransomware, and the Ims00rry ransomware.

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Pierluigi Paganini

(SecurityAffairs – JSWorm, ransomware)

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Pierluigi Paganini

Pierluigi Paganini is member of the ENISA (European Union Agency for Network and Information Security) Threat Landscape Stakeholder Group and Cyber G7 Group, he is also a Security Evangelist, Security Analyst and Freelance Writer. Editor-in-Chief at "Cyber Defense Magazine", Pierluigi is a cyber security expert with over 20 years experience in the field, he is Certified Ethical Hacker at EC Council in London. The passion for writing and a strong belief that security is founded on sharing and awareness led Pierluigi to find the security blog "Security Affairs" recently named a Top National Security Resource for US. Pierluigi is a member of the "The Hacker News" team and he is a writer for some major publications in the field such as Cyber War Zone, ICTTF, Infosec Island, Infosec Institute, The Hacker News Magazine and for many other Security magazines. Author of the Books "The Deep Dark Web" and “Digital Virtual Currency and Bitcoin”.