Keypoints
- CryptoWire is implemented in AutoIt and distributed mainly through phishing emails.
- It copies itself to C:Program FilesCommon Files and registers a scheduled task for persistence.
- Performs local network discovery and saves results to desktop as domaincheck.txt while searching for accounts to expand encryption scope.
- Deletes the Recycle Bin and Volume Shadow Copies to inhibit system recovery before encryption.
- Encrypted files use the pattern [original name].encrypted.[original extension] and a ransom GUI requests payment for decryption.
- The ransomware sometimes contains the decryption key in the AutoIt script or sends the key and system info to a C2 server.
- Observed IOCs include MD5 hashes and a C2 URL: hxxp://194.156.98[.]51/bot/log.php.
MITRE Techniques
- [T1064] Scripting – Implemented with AutoIt script to perform infection and payload actions (‘CryptoWire ransomware is … characterized by being created with Autoit script.’)
- [T1053.005] Scheduled Task/Job – Registers a scheduled task to maintain persistence (‘The ransomware copies itself to the “CProgram FilesCommon Files” path and registers a task scheduler to maintain continuity.’)
- [T1135] Network Share Discovery – Searches the locally connected network environment to expand file encryption ( ‘To expand file encryption, search the locally connected network environment, save it as domaincheck.txt on the desktop…’)
- [T1087] Account Discovery – Searches for created accounts found during network discovery (‘…and search for the created account.’)
- [T1490] Inhibit System Recovery – Deletes the Recycle Bin and Volume Shadow Copies to prevent recovery (‘Additionally, delete the Recycle Bin and Volume Shadow Copy to prevent recovery.’)
- [T1486] Data Encrypted for Impact – Encrypts files and appends an encryption extension, then displays a ransom UI (‘The encrypted file is in the form of [existing file name].encrypted.[existing extension], and a window pops up asking you to purchase a decryption key…’)
- [T1041] Exfiltration Over C2 – Sends decryption key and infected system information to an attacker-controlled server (‘…sends the decryption key along with the infected system information to the attacker’s server…’)
- [T1071] Application Layer Protocol – Uses HTTP to communicate with a C2 endpoint (evidenced by connection to the C2 URL shown in source code and logs)
Indicators of Compromise
- [MD5] Sample hashes – cd4a0b371cd7dc9dab6b442b0583550c, a410d4535409a379fbda5bb5c32f6c9c
- [C2 URL] Command-and-control endpoint – hxxp://194.156.98[.]51/bot/log.php (used to receive/exfiltrate decryption key and system info)
- [Filename/Extension] Encrypted file pattern – [original name].encrypted.[original extension] (ransom note GUI displayed on infected host)
A technical summary of the procedure: CryptoWire arrives most commonly via phishing and executes as an AutoIt script. On execution it copies itself to C:Program FilesCommon Files and creates a scheduled task for persistence. The malware performs local network discovery (saving results to domaincheck.txt on the desktop) and searches for accounts to broaden its reach, then proceeds to encrypt files using the pattern [filename].encrypted.[extension] while presenting a ransom dialog.
Before encryption completes, the ransomware attempts to prevent recovery by deleting the Recycle Bin and removing Volume Shadow Copies. Some samples embed a decryption key directly in the AutoIt script; others gather infected-system information and send the decryption key to a remote C2 endpoint via HTTP. Observed IOCs include two MD5 sample hashes and the C2 URL hxxp://194.156.98[.]51/bot/log.php.
Detection and mitigation recommendations: block known IOCs at network and endpoint layers, scan suspicious attachments before execution, maintain up-to-date antivirus signatures, and ensure offline backups and shadow copies are protected to reduce impact from encryption and recovery-prevention actions.
Read more: https://asec.ahnlab.com/ko/62868/