{ "family": "pycrypter", "sample_count": 1, "category": "ransomware", "description": "

Executive Summary

\nPyCrypter is a classification for file-encrypting Ransomware written entirely in Python. While traditionally ransomware was written in C++ or Delphi for speed and low-level system access, the use of Python (often compiled into a standalone executable using tools like PyInstaller or py2exe) has become increasingly common. It allows for rapid development, easy cross-platform porting, and occasionally bypasses older AV engines that struggle to decompile packaged Python scripts.\n\n

Infection Vector and Technical Capabilities

\nPyCrypter is typically distributed via targeted spear-phishing campaigns, malicious macros embedded in Office documents, or deployed directly by attackers who have compromised external-facing RDP servers.\n\nUpon execution, PyCrypter leverages Python's extensive standard library for its attack:\n\n\n

Threat Assessment

\nDespite being written in a high-level scripting language, PyCrypter is highly destructive. It represents a critical tier-one security incident resulting in an immediate loss of data availability. The use of Python also makes the malware easily modifiable by different threat actors, leading to numerous distinct variants.\n\n

Incident Response and Remediation

\n", "cta": "Published by the SystemHelpdesk team.", "aliases": [ "Ransom.PyCrypter", "Python.Ransomware", "Win32/Filecoder.Python" ], "enrichment_level": "expert-seo", "faq": [ { "@type": "Question", "name": "What is Pycrypter and what threat category does it belong to?", "acceptedAnswer": { "@type": "Answer", "text": "Pycrypter is classified as a Ransomware. Documented across security telemetry, it is engineered to execute unauthorized operations, establish persistent footholds on target endpoints, and facilitate malicious campaigns targeting enterprise and individual environments." } }, { "@type": "Question", "name": "How does Pycrypter establish persistence and evade defensive controls?", "acceptedAnswer": { "@type": "Answer", "text": "Pycrypter typically establishes persistence through registry run keys, scheduled tasks, or service installations, while evading signature-based antivirus solutions through code obfuscation, memory injection, or anti-analysis sandbox checks." } }, { "@type": "Question", "name": "What are the essential incident response steps for mitigating a Pycrypter compromise?", "acceptedAnswer": { "@type": "Answer", "text": "Security teams responding to Pycrypter should immediately isolate affected endpoints from the network, perform memory triage to capture volatile forensic artifacts, audit registry and startup persistence mechanisms, revoke exposed user credentials, and restore systems from verified, clean backups." } }, { "@type": "Question", "name": "What cryptographic algorithms and file targeting techniques does Ransom.PyCrypter employ during execution?", "acceptedAnswer": { "@type": "Answer", "text": "Ransom.PyCrypter typically leverages hybrid cryptographic architectures combining symmetric stream or block ciphers (such as AES-256 or ChaCha20) for rapid file encryption with asymmetric algorithms (such as RSA-2048 or Curve25519) to securely protect the session keys. It aggressively targets sensitive file extensions including corporate documents, databases, virtual disks, and backups while systematically executing commands to delete Volume Shadow Copies (vssadmin delete shadows /all /quiet) and disable system recovery options." } }, { "@type": "Question", "name": "Are decryptors available for Ransom.PyCrypter, and what is the recommended recovery procedure?", "acceptedAnswer": { "@type": "Answer", "text": "Decryption availability for Ransom.PyCrypter depends on whether security researchers or law enforcement (such as the No More Ransom initiative) have recovered the master private keys or discovered flaws in its key generation routines. Victims should never pay the extortion demand, as payment fuels criminal operations without guaranteeing file restoration. The recommended recovery procedure entails isolating infected hosts, conducting forensic disk imaging, identifying the root access vector, and restoring validated systems from immutable offline backups." } } ], "faq_count": 5, "mitre_attack": [ "T1486", "T1490", "T1059.006" ], "cisa_advisory": null, "last_updated": "2026-10-15", "type": "Ransomware (Python-based)", "target_industries": [ "Healthcare", "Critical Infrastructure", "Enterprise" ], "motivation": "Financial Extortion", "threat_actors": [ "Unknown / Cybercriminal" ], "target_geographies": [ "Global" ], "attack_stage": [ "defense_evasion", "impact" ], "ecosystem": [ "windows_pe" ], "is_emerging": false, "mitre_attack_detail": [ { "id": "T1486", "name": "Data Encrypted for Impact", "tactic": "Impact" }, { "id": "T1490", "name": "Inhibit System Recovery (Behaviorally blocking the deletion of backups)", "tactic": "Impact" }, { "id": "T1059.006", "name": "Command and Scripting Interpreter: Python", "tactic": "Execution" } ], "containment_steps": [ "Immediately isolate affected host(s) from the internal network (disconnect physical Ethernet and disable Wi-Fi/Bluetooth) to prevent Pycrypter from spreading laterally or encrypting network-attached storage (NAS) and shared SMB volumes.", "Preserve volatile system memory (RAM capture) on a representative endpoint before attempting a reboot or power-down, as Pycrypter symmetric encryption keys or uncompiled payload components may still reside in memory.", "Audit process execution logs and terminate active scripting interpreters (e.g. PowerShell, CMD, WScript) or commands executing 'vssadmin.exe delete shadows' or 'wbadmin' used by Pycrypter to inhibit recovery.", "Investigate the initial compromise vector (such as exposed RDP instances, spearphishing attachments, or vulnerable edge gateways) and enforce an immediate credential reset for all compromised Active Directory accounts.", "Restore critical assets and databases exclusively from verified, air-gapped, or immutable offline backups once the Pycrypter binary and related persistence hooks are eradicated." ], "what_to_avoid": [ "Do not restart or power cycle infected systems prematurely; doing so destroys volatile RAM encryption keys and may trigger bootloader locking logic embedded in Pycrypter.", "Avoid negotiating or paying the extortion demand without prior forensic evaluation and consultation with incident response specialists, as payment does not guarantee data recovery.", "Do not connect clean backup drives or external storage to the affected network until Pycrypter eradication is completely verified." ], "target_platforms": [ "Windows 11", "Windows 10", "Windows Server 2022", "Windows Server 2019" ] }