Rostpay

Category: ransomware · Aliases: Trojan.Rostpay, Ransom.Locker.Rostpay, Win32/Rostpay · Sample count (EMBER 2018): 1 · Enrichment: insufficient_information · Updated: 2026-07-02T06:57:41Z

Category: RansomwareActor: Unknown / CybercriminalIndustry: Global / OpportunisticMotivation: Opportunistic

Overview

Executive Summary

Rostpay is a malicious Trojan that frequently exhibits destructive behavior, often operating as a "locker" ransomware or a data-wiping utility. Unlike sophisticated, enterprise-targeting ransomware (which uses strong cryptography to hold files hostage), Rostpay variants often simply lock the user's screen or scramble files in a crude, often irreversible manner to extort a small ransom or simply cause disruption.

Infection Vector and Technical Capabilities

Rostpay is predominantly distributed through deceptive software downloads, fake cracks/keygens on untrustworthy websites, or via malspam campaigns targeting individuals rather than large enterprises. Upon successful execution, Rostpay initiates a disruptive attack sequence:

Screen Locking (Locker Ransomware): Many variants of Rostpay do not encrypt files. Instead, they disable the Task Manager, block the keyboard (except for specific inputs), and display a persistent, full-screen ransom note demanding payment (often via premium SMS or low-value cryptocurrency transfers).
Crude Data Disruption: If the variant does target files, it often uses simple, flawed encryption (like XOR obfuscation) or simply overwrites the file headers, corrupting the data rather than securely encrypting it for later decryption.
Persistence: Rostpay ensures it survives system reboots by aggressively modifying the Windows Registry (e.g., altering the `Winlogon\Shell` key to launch the malware instead of `explorer.exe`).

Threat Assessment

While a Rostpay infection might lack the sophistication of an APT or major ransomware gang, it represents a severe, immediate loss of system availability. The crude nature of the malware means that even if a ransom is paid, data recovery is often impossible because the files were corrupted rather than properly encrypted.

Incident Response and Remediation

Safe Mode Recovery: Because many Rostpay variants rely on simple registry modifications for screen locking, booting the system into Windows "Safe Mode with Command Prompt" often bypasses the malware's execution.
Registry Repair: From Safe Mode, incident responders can manually use `regedit` to repair the modified `Winlogon` keys or remove the malicious `Run` entries.
System Re-imaging: Given the high likelihood of irreversible file corruption and the difficulty of ensuring complete removal, the safest remediation strategy is a complete bare-metal wipe and re-image from a trusted backup.

Known aliases

Threat reports may refer to this family under multiple names:

MITRE ATT&CK Techniques

This family has been observed using the following ATT&CK techniques: T1486 T1491 T1547.001

Generated Detections (Boilerplate)

These YARA and Sigma rules are auto-generated based on the family name and aliases. They must be heavily tuned before deployment in a production environment.

YARA Rule

rule MALWARE_WIN_ROSTPAY {
    meta:
        description = "Detects Rostpay (ransomware)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "rostpay" ascii wide nocase
        $s2 = "trojan.rostpay" ascii wide nocase
        $s3 = "ransom.locker.rostpay" ascii wide nocase
        $s4 = "win32/rostpay" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Rostpay Activity
id: 5b63fb0bfcc96d62e302a8c7c616fb6b
status: experimental
description: Detects generic indicators of the rostpay malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*rostpay*"
            - "*trojan.rostpay*"
            - "*ransom.locker.rostpay*"
            - "*win32/rostpay*"
    condition: selection
level: medium

References & External Analysis

Search "rostpay" on VirusTotal (External Analysis)

Frequently Asked Questions

How do I remove the Rostpay Ransomware from Windows?

Manual removal of Rostpay is highly discouraged as it may leave persistence mechanisms intact. We recommend disconnecting the device from the internet and utilizing a professional incident response service or enterprise-grade EDR software to conduct a full forensic sweep.

Is Rostpay a virus or a Ransomware?

Rostpay is classified as a Ransomware. Unlike traditional viruses that infect files, modern malware like Rostpay typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.

What are the main symptoms of a Rostpay infection?

Symptoms of Rostpay can include unexpected system slowness, unauthorized outbound network traffic to unknown IP addresses, disabled security software, and suspicious background processes running from AppData or Temp directories.

Related Families (Category: ransomware)

Explore other malware families in the same category:

Protect Your Network Against Ransomwares

Want to prevent Rostpay and similar threats from compromising your organization? Read our comprehensive defensive guide: Ransomware Protection Guide.

Need help with an active incident? Published by the SystemHelpdesk team.

Machine-readable

Get this profile as JSON: https://jordanricky1604-ship-it.github.io/malware-families-catalog/api/rostpay.json

Ecosystem & Interactive Environments

This profile is part of the Malware Families Catalog, a public dataset of 2,899 malware families. The catalog is also published across our ecosystem: Hugging Face, Kaggle, Zenodo, Replit, StackBlitz, CodeSandbox, and CodePen.