{
  "family": "winsecsrv",
  "sample_count": 45,
  "category": "trojan",
  "description": "Trojan:Win32/Winsecsrv is a persistent trojan and backdoor that heavily relies on masquerading as a legitimate Windows security or system service to evade detection by users and basic administrative tools.<br><br><b>Understanding Winsecsrv</b><br>To the end-user, the system appears normal. If they open the Task Manager, they might see a process with a plausible-sounding name like `Windows Security Service` or `WinSecSrv.exe`. For a security analyst, this is a classic technique of Masquerading (`T1036`). The malware intentionally adopts the naming conventions of core Microsoft OS components to blend in with the background noise of the operating system, hoping administrators will overlook it during manual triage.<br><br><b>Execution and Evasion Strategies</b><br>Winsecsrv is typically dropped by exploit kits or spearphishing campaigns. Upon execution, it moves its core payload into the `%SystemRoot%\\System32` directory. It then utilizes the Windows Service Control Manager (`sc.exe` or APIs like `CreateService`) to install itself as a background service (`T1543.003`). This grants it extreme persistence (starting automatically before a user even logs in) and elevated `SYSTEM` privileges. Once running as a service, the trojan typically acts as a backdoor, opening ports to receive commands, exfiltrating data, or downloading secondary payloads.<br><br><b>Indicators of Compromise & Impact</b><br>The impact is a fully compromised endpoint with the malware operating at the highest privilege level (`SYSTEM`). EDR platforms will flag the unauthorized creation of a new Windows service by an unknown binary. Incident responders should audit the Windows Services list (`services.msc`) for entries lacking a description, lacking a legitimate Microsoft digital signature, or pointing to executables outside the standard `C:\\Windows\\System32` path (though Winsecsrv often tries to hide there). Network logs will reveal anomalous outbound traffic originating from this fake service.",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [],
  "faq_count": 0,
  "mitre_attack": [
    "T1036.005",
    "T1055",
    "T1105",
    "T1543.003",
    "T1489"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-06-09",
  "mitre_attack_detail": [
    {
      "id": "T1036.005",
      "name": "Masquerading: Match Legitimate Name or Location",
      "tactic": "Defense Evasion"
    },
    {
      "id": "T1543.003",
      "name": "Create or Modify System Process: Windows Service",
      "tactic": "Persistence"
    },
    {
      "id": "T1105",
      "name": "Ingress Tool Transfer",
      "tactic": "Command and Control"
    },
    {
      "id": "T1055",
      "name": "Process Injection",
      "tactic": "Defense Evasion"
    },
    {
      "id": "T1489",
      "name": "Service Stop",
      "tactic": "Impact"
    }
  ],
  "containment_steps": [
    "Immediately isolate the endpoint from the network; running as a `SYSTEM` level service grants the attacker total control over the machine.",
    "Utilize EDR or the command line (`sc stop` and `sc delete`) to forcefully terminate and remove the malicious service entry.",
    "Capture a forensic memory image to extract the configuration of the backdoor and identify the C2 server it was communicating with.",
    "Due to the `SYSTEM` level compromise, the most secure remediation is a complete, clean rebuild of the operating system."
  ],
  "what_to_avoid": [
    "Do not trust the name of any process in Task Manager; always verify the digital signature and file path of suspected services.",
    "Avoid assuming the threat is contained just by deleting the executable; the Service Control Manager will throw errors and may attempt to restart it."
  ],
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ]
}