{
  "family": "renos",
  "sample_count": 24,
  "category": "rogueware",
  "description": "TrojanDownloader:Win32/Renos is a widespread trojan downloader notorious for facilitating the delivery of rogue security software (scareware) and other malicious payloads.<br><br><b>Understanding Renos</b><br>For the general public, a Renos infection is the starting point of a nightmare scenario where the computer is suddenly bombarded with fake virus alerts claiming the system is critically infected. For incident responders, Renos is recognized as the staging mechanism—a small, stealthy downloader whose sole purpose is to quietly fetch and execute the highly visible, disruptive scareware payload.<br><br><b>Execution and TTPs</b><br>Renos typically infects systems via drive-by downloads from compromised websites, exploit kits, or as an attachment in spam emails. Once executed, it does not immediately display any symptoms. Instead, it operates silently in the background, connecting to a hardcoded list of Command and Control (C2) servers. It downloads the secondary payload—often rogue AV families like Spyware Protect 2009 or Antivirus XP—and executes it. Renos establishes its own persistence by dropping a dynamically named DLL or executable into the <code>%SystemRoot%\\System32</code> directory and creating a corresponding Registry Run key.<br><br><b>Indicators of Compromise (IoCs)</b><br>Forensic analysis of a Renos infection often reveals unexpected outbound HTTP GET requests downloading executable files to the <code>%Temp%</code> directory. Threat hunters should monitor for the sudden creation of highly randomized filenames in the System32 directory and the sudden, aggressive termination of legitimate anti-virus processes (a common tactic of the downloaded scareware).",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [],
  "faq_count": 0,
  "mitre_attack": [
    "T1189",
    "T1105",
    "T1547.001",
    "T1489",
    "T1059.003"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-06-09",
  "mitre_attack_detail": [
    {
      "id": "T1189",
      "name": "Drive-by Compromise",
      "tactic": "Initial Access"
    },
    {
      "id": "T1105",
      "name": "Ingress Tool Transfer",
      "tactic": "Command and Control"
    },
    {
      "id": "T1547.001",
      "name": "Boot or Logon Autostart Execution: Registry Run Keys / Startup Folder",
      "tactic": "Persistence"
    },
    {
      "id": "T1489",
      "name": "Service Stop",
      "tactic": "Impact"
    },
    {
      "id": "T1059.003",
      "name": "Command and Scripting Interpreter: Windows Command Shell",
      "tactic": "Execution"
    }
  ],
  "containment_steps": [
    "Disconnect the endpoint from the network to prevent Renos from downloading additional scareware or ransomware payloads.",
    "Boot the infected system into 'Safe Mode with Networking' to bypass the aggressive blocking mechanisms of the dropped rogue AV.",
    "Utilize specialized malware removal tools (like Malwarebytes) to scan and eradicate both the Renos downloader and the scareware payload.",
    "Audit the Windows Registry for rogue 'Run' keys and remove any randomly named DLLs dropped in the System32 directory."
  ],
  "what_to_avoid": [
    "Do not provide any credit card information or pay the 'registration fee' demanded by the fake anti-virus software downloaded by Renos.",
    "Avoid attempting manual removal of the scareware without first addressing the Renos downloader; otherwise, the payload will simply be re-downloaded."
  ],
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ]
}