{
  "family": "winexec",
  "sample_count": 2,
  "category": "ransomware",
  "description": "HackTool:Win32/Winexec (often associated with PsExec or similar remote execution utilities) is a heuristic detection for tools capable of executing commands and launching processes on remote Windows systems. While `winexec` can refer to a specific legacy Windows API function, in threat detection, it generally flags administrative tools that have been weaponized by threat actors to facilitate lateral movement across a compromised network.<br><br><b>Understanding Winexec (Remote Execution)</b><br>To an end-user, this activity is completely invisible. For a security architect, the unauthorized use of remote execution tools is a critical indicator of an active breach. Tools like PsExec (part of Sysinternals) are legitimate administrative utilities. However, because they are so powerful, attackers frequently use them ('Living off the Land') to move laterally (`T1569.002`) without needing to drop custom, easily detectable malware.<br><br><b>Execution and Lateral Movement Mechanics</b><br>Once an attacker compromises a single machine and obtains administrative credentials (often via dumping LSASS - `T1003`), they will use a tool flagged as Winexec to execute commands on other machines in the domain. These tools typically work by connecting to the remote machine via SMB (`T1021.002`), dropping a temporary service executable into the `C:\\Windows\\Admin$`, and then starting that service (`T1543.003`) to execute the desired payload (like a Cobalt Strike beacon or ransomware) with `SYSTEM` privileges on the target.<br><br><b>Indicators of Compromise & Impact</b><br>The impact is rapid, devastating lateral movement leading to domain-wide compromise. Host-based IoCs include Windows Event Logs (Event ID 7045 - A new service was installed in the system) referencing unusual service names (like `PSEXESVC`). Network IoCs include high volumes of SMB traffic (Port 445) originating from a non-administrative workstation targeting numerous other endpoints. EDR will flag `psexec.exe` or `wmic.exe` executing with suspicious command-line arguments.",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [],
  "faq_count": 0,
  "mitre_attack": [
    "T1543.003",
    "T1021.002",
    "T1569.002"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-06-09",
  "mitre_attack_detail": [
    {
      "id": "T1569.002",
      "name": "System Services: Service Execution (Using PsExec/winexec)",
      "tactic": "Execution"
    },
    {
      "id": "T1021.002",
      "name": "Remote Services: SMB/Windows Admin Shares",
      "tactic": "Lateral Movement"
    },
    {
      "id": "T1543.003",
      "name": "Create or Modify System Process: Windows Service",
      "tactic": "Persistence"
    }
  ],
  "containment_steps": [
    "Identify the source machine initiating the remote execution commands and immediately isolate it from the network.",
    "Assume the credentials used to authenticate the remote execution are compromised; initiate an immediate enterprise-wide password reset for that account.",
    "Review Windows Event Logs (Security and System) across the domain to track the lateral movement and identify all compromised hosts.",
    "Implement strict network segmentation and firewall rules to prevent workstation-to-workstation SMB communication."
  ],
  "what_to_avoid": [
    "Do not ignore alerts for legitimate tools like PsExec if they originate from non-IT subnets or occur outside standard maintenance windows.",
    "Avoid relying solely on file blocking; attackers can rename the executable or use built-in alternatives like WMI or PowerShell Remoting."
  ],
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ]
}