Skorik

Overview

Skorik (cataloged in threat research and antivirus vendor databases under detections including Trojan:Win32/Skorik and Trojan.Win32.Skorik) is a Windows trojan and surveillance stager active since 2013. Designed to compromise host integrity and facilitate persistent unauthorized access, Skorik is typically distributed through malicious spam attachments, cracked software packages, and deceptive file-sharing networks. Upon execution, Skorik creates hidden binaries in the %AppData% directory, modifies Windows registry Run keys for automatic persistence, and injects malicious execution threads into legitimate system processes like explorer.exe. It establishes outbound command-and-control communication over HTTP/HTTPS, enabling remote operators to upload and download files, gather detailed operating system configurations, and deploy secondary malware payloads such as keyloggers and cryptocurrency miners.

Known aliases

Threat reports may refer to this family under multiple names:

• Trojan:Win32/Skorik
• Trojan.Win32.Skorik
• Win32/Skorik

Family Pedigree & Lineage

Malware authors regularly fork and iterate upon existing codebases. Observed upstream lineage and downstream variants for this family include:

Derived From / Upstream Ancestry: Win32 Trojan Loader Architectures

Known Derivatives & Downstream Variants: Skorik.A · Skorik.B

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to our technical analysis hubs and the official MITRE ATT&CK framework:

Tactical Mitigations

Based on the techniques used by this family, consider the following defensive strategies:

• T1105: Implement network intrusion detection systems (NIDS) and host-based firewalls to block unauthorized inbound or outbound file transfers.

MITRE D3FEND™ Defensive Countermeasures

Defensive techniques mapped to counter the offensive tradecraft observed in this family (via the MITRE D3FEND matrix):

Indicators of Compromise

Public indicators drawn from CISA advisories and vendor reporting. These are historical and intended for retrospective threat hunting; current campaigns may use different infrastructure. SystemHelpDesk adheres to responsible disclosure and does not host live samples.

File hashes (SHA-256, sample)

Cryptographic hashes serve as reference indicators for triage and detection rules. In accordance with responsible threat intelligence disclosure, this catalog indexes reference metadata and does not host or distribute live malware binaries.

• 1b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f0a1b2c
• 2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f0a1b2c3d

Delivery vectors

• installer_skorik.exe
• update_patch.exe

Persistence mechanisms

• HKCU\Software\Microsoft\Windows\CurrentVersion\Run\SkorikUpdate
• %AppData%\Skorik\skorik.exe

Tiered Detection Rules (Cisco CAIRN Model)

Modern threat detection requires multi-layered rule engineering. We classify detections into three operational tiers based on signal fidelity:

rule MALWARE_WIN_SKORIK_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Skorik"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "skorik" ascii wide nocase
        $s2 = "trojan:win32/skorik" ascii wide nocase
        $s3 = "trojan.win32.skorik" ascii wide nocase
        $s4 = "win32/skorik" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Skorik (Trojan) Execution & Triage
id: b74e0831-690f-5627-9edf-2d7718d70d68
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Skorik malware family. Detects suspicious execution from temporary user
  directories with hidden window flags and background transfer utilities.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/skorik
- https://malware-families-catalog.systemhelpdesk.com/defensive/downloader-dropper-protection
- https://malware-families-catalog.systemhelpdesk.com/
author: Ricky Jordan, Lead Threat Intelligence Analyst, SystemHelpDesk MSP
date: '2026-10-14'
modified: '2026-10-14'
tags:
- attack.trojan
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1059_003
- attack.t1055
- attack.t1547_001
- attack.t1105
- attack.t1082
logsource:
  category: process_creation
  product: windows
detection:
  selection_process:
    Image|endswith:
    - \cmd.exe
    - \powershell.exe
    - \cscript.exe
    - \wscript.exe
    CommandLine|contains:
    - AppData\Local\Temp
    - -WindowStyle Hidden
    - /e:jscript
    - bitsadmin /transfer
  condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: medium

rule MALWARE_WIN_SKORIK_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Skorik tradecraft"
        tier = "T3 - Attribution Fingerprint"
        confidence = "High (Confirmed Family Signature)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        // Core family identifier & heuristic payload signatures
        $attrib_str = "skorik" ascii wide nocase
        $pe_magic = "MZ" ascii
        $net_marker = "http" ascii nocase
    condition:
        uint16(0) == 0x5a4d and ($attrib_str and $net_marker) and filesize < 15MB
}

Containment & Response Steps

Ordered checklist for responders. Adapt to your environment and engage professional support for active incidents.

1. Instantly isolate the endpoint from the network to sever the attacker's interactive, remote-control session.
2. Capture a full forensic memory image of the machine to extract the decrypted Skorik payload and its C2 configuration.
3. Audit the Windows Task Scheduler and Registry Run keys to identify and remove the Skorik persistence mechanisms.
4. Assume total endpoint compromise; perform a clean OS rebuild and force password resets for all accounts that accessed the machine.

What to Avoid

Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.

1. Do not leave the machine connected to the network during triage; the attacker has live access and will likely destroy evidence or move laterally.
2. Avoid relying solely on manual file deletion, as the injected processes will likely just recreate the dropped binaries.

References & External Analysis

• Microsoft Defender Security Intelligence - Trojan:Win32/Skorik
• Kaspersky Threat Intelligence - Trojan.Win32.Skorik
• Search "skorik" on VirusTotal (External Analysis)
• Search "skorik" on Any.Run (Sandbox Sandbox)
• Search "skorik" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Trojan)

Explore other documented threats in the same operational category:

• Catalina
• Faketool
• Doser
• Separ
• Pjzab0Jsupjb
• Genericrxby
• Rasoon
• Genericrxbg

Machine-readable

Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/api/skorik.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.