{
  "family": "lsslogger",
  "sample_count": 4,
  "category": "trojan",
  "description": "Trojan:Win32/Lsslogger is a specialized, stealthy trojan designed exclusively for credential theft, specifically operating as a **Keylogger**. Unlike broad information stealers that simply scrape browser files, Lsslogger focuses on intercepting user input at the operating system level, capturing passwords, emails, and sensitive communications as they are typed, before they are encrypted by applications.<br><br><b>Understanding Lsslogger (Keyloggers)</b><br>To an end-user, Lsslogger is completely invisible; it does not display windows or impact performance. For a security analyst, a keylogger represents a severe breach of confidentiality. It implies that any credential entered on the compromised machine (including highly secure passwords not saved in browsers) is now in the hands of the attacker, often facilitating immediate lateral movement.<br><br><b>Execution and Interception Mechanics</b><br>Lsslogger is typically dropped by a primary infection vector, such as a malicious Office macro (`T1566.001`) or a downloader trojan. Once executed, it establishes persistence via the Registry Run keys or hidden scheduled tasks (`T1547.001`). Its core function relies on hooking Windows APIs (`T1056.001`). It uses functions like `SetWindowsHookEx` to intercept keyboard events before they reach the target application (like a web browser or VPN client). The captured keystrokes are recorded into a hidden, often encrypted, log file stored in the `%Temp%` or `System32` directory. Periodically, Lsslogger compresses this log file and exfiltrates it to the attacker, often using simple protocols like SMTP (emailing the logs to a disposable address) or FTP upload (`T1048.003`).<br><br><b>Indicators of Compromise & Impact</b><br>The impact is the total compromise of all accounts accessed from the infected machine. Host-based IoCs include EDR alerts for 'Suspicious API Hooking' targeting input functions, and the presence of rapidly growing, encrypted `.dat` or `.log` files in user profile directories. Network IoCs often include anomalous outbound SMTP (port 25, 465, 587) or FTP (port 21) traffic originating from a standard Windows process rather than a legitimate email client.",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [],
  "enrichment_level": "expert-seo",
  "faq": [],
  "faq_count": 0,
  "mitre_attack": [
    "T1055",
    "T1056.001",
    "T1048.003",
    "T1547.001"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-06-09",
  "mitre_attack_detail": [
    {
      "id": "T1056.001",
      "name": "Input Capture: Keylogging (API Hooking via SetWindowsHookEx)",
      "tactic": "Collection"
    },
    {
      "id": "T1055",
      "name": "Process Injection (Injecting hooks into other processes)",
      "tactic": "Defense Evasion"
    },
    {
      "id": "T1048.003",
      "name": "Exfiltration Over Alternative Protocol (Exfiltrating logs via SMTP/FTP)",
      "tactic": "Exfiltration"
    },
    {
      "id": "T1547.001",
      "name": "Boot or Logon Autostart Execution",
      "tactic": "Persistence"
    }
  ],
  "containment_steps": [
    "Assume ALL credentials typed on the machine (corporate passwords, personal banking, SSH keys) are compromised and force immediate resets from a known-clean device.",
    "Isolate the endpoint to stop the active exfiltration of the keylogger log files.",
    "Analyze the memory of running processes to identify the specific module performing the API hooking and extract its configuration (which will reveal the attacker's email/FTP drop zone).",
    "Review authentication logs across the network for the compromised user's credentials to detect if the attacker has already used the stolen passwords for lateral movement."
  ],
  "what_to_avoid": [
    "Do not assume multi-factor authentication (MFA) provides complete protection; while it helps, a keylogger will capture the username and password, giving the attacker half of what they need.",
    "Avoid relying solely on file deletion; advanced keyloggers often inject their hooking DLLs into legitimate processes like `explorer.exe`, requiring a reboot or process termination to fully unload."
  ],
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ]
}