{
  "family": "staem",
  "sample_count": 1,
  "category": "trojan",
  "description": "<h3>Executive Summary</h3>\n\"Staem\" (a deliberate misspelling of \"Steam\") is a classification for a specific type of Phishing Trojan and Information Stealer designed to target users of the Valve Steam gaming platform. Its primary objective is the theft of Steam account credentials, bypassing Steam Guard (2FA), and ultimately stealing valuable in-game inventories (like CS:GO skins) and hijacking the account for resale.\n\n<h3>Infection Vector and Technical Capabilities</h3>\nStaem trojans are heavily distributed via social engineering within the Steam community itself. Attackers compromise one account, then message the victim's friends list with links to fake tournament sign-ups, \"free skin\" giveaways, or deceptive trading sites. The malware is often disguised as a VoIP client (like a fake TeamSpeak or Discord update) required to join a game.\n\nUpon execution, it performs a highly targeted data harvesting operation:\n<ul>\n<li><strong>Credential Phishing Overlays:</strong> The trojan often operates by detecting when the legitimate Steam client is launched. It then immediately suspends the legitimate process and overlays a pixel-perfect, fake Steam login window on top. When the user enters their username and password, it is captured by the malware.</li>\n<li><strong>Steam Guard Bypass (SSFN File Theft):</strong> To bypass Steam's two-factor authentication, the malware actively hunts for the hidden `ssfn*` files located in the Steam installation directory. These files act as persistent authorization tokens.</li>\n<li><strong>Data Exfiltration:</strong> The stolen credentials and the `ssfn` files are bundled and transmitted to the attacker's C2 server. The attacker can then use these files to log into the victim's account from a remote machine without triggering a Steam Guard code request.</li>\n</ul>\n\n<h3>Threat Assessment</h3>\nWhile a Staem infection primarily targets personal gaming assets rather than corporate financial data, it represents a significant security breach. The hijacked account is immediately used to spread the malware further. Furthermore, users frequently reuse passwords; a compromised gaming password could lead to the compromise of the user's primary email or banking accounts.\n\n<h3>Incident Response and Remediation</h3>\n<ul>\n<li><strong>Immediate Account Recovery:</strong> The victim must immediately attempt to recover their account via Steam Support, locking the account to prevent the trade of valuable inventory items.</li>\n<li><strong>Global Credential Reset:</strong> A complete password reset for the Steam account and ANY other service that shares the same password must be performed from a *different, clean device*.</li>\n<li><strong>Endpoint Eradication:</strong> Run a full system scan using a reputable enterprise antivirus solution to remove the Staem executable and any associated keylogging components.</li>\n</ul>",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [
    "Trojan.SteamStealer",
    "PWS.Steam",
    "Phish.Staem"
  ],
  "enrichment_level": "expert-seo",
  "faq": [
    {
      "@type": "Question",
      "name": "What is Staem and what threat category does it belong to?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Staem is classified as a Trojan. Documented across security telemetry, it is engineered to execute unauthorized operations, establish persistent footholds on target endpoints, and facilitate malicious campaigns targeting enterprise and individual environments."
      }
    },
    {
      "@type": "Question",
      "name": "How does Staem establish persistence and evade defensive controls?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Staem typically establishes persistence through registry run keys, scheduled tasks, or service installations, while evading signature-based antivirus solutions through code obfuscation, memory injection, or anti-analysis sandbox checks."
      }
    },
    {
      "@type": "Question",
      "name": "What are the essential incident response steps for mitigating a Staem compromise?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Security teams responding to Staem should immediately isolate affected endpoints from the network, perform memory triage to capture volatile forensic artifacts, audit registry and startup persistence mechanisms, revoke exposed user credentials, and restore systems from verified, clean backups."
      }
    },
    {
      "@type": "Question",
      "name": "What secondary payloads and staging behaviors are commonly associated with Trojan.SteamStealer?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Trojan.SteamStealer frequently operates as a loader or dropper designed to establish a foothold before downloading and executing secondary high-impact malware payloads. Depending on the threat actor's objectives, these dropped modules can range from ransomware and banking injects to modular infostealers and remote management backdoors."
      }
    },
    {
      "@type": "Question",
      "name": "How can security operations teams effectively detect and hunt for Trojan.SteamStealer across enterprise endpoints?",
      "acceptedAnswer": {
        "@type": "Answer",
        "text": "Defenders should hunt for Trojan.SteamStealer by deploying behavioral endpoint detection and response (EDR) rules that monitor suspicious process spawning (such as cmd.exe or powershell.exe spawned from office documents or temporary directories), anomalous outbound network connections from non-browser binaries, and unauthorized modifications to Windows Run keys and scheduled task registries."
      }
    }
  ],
  "faq_count": 5,
  "mitre_attack": [
    "T1555.003",
    "T1539",
    "T1056.002",
    "T1114"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-10-15",
  "type": "Information Stealer / Phishing Trojan",
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ],
  "attack_stage": [
    "execution",
    "persistence"
  ],
  "ecosystem": [
    "windows_pe"
  ],
  "is_emerging": false,
  "mitre_attack_detail": [
    {
      "id": "T1555.003",
      "name": "Credentials from Web Browsers",
      "tactic": "Unknown"
    },
    {
      "id": "T1539",
      "name": "Steal Web Session Cookie (Abusing active authenticated sessions to perform social media fraud)",
      "tactic": "Credential Access"
    },
    {
      "id": "T1056.002",
      "name": "Input Capture: GUI Input Capture (Monitoring active window titles for targeted banks)",
      "tactic": "Collection"
    },
    {
      "id": "T1114",
      "name": "Email Collection (Harvesting addresses for spamming)",
      "tactic": "Collection"
    }
  ],
  "containment_steps": [
    "Sever network connectivity for the flagged endpoint to terminate persistent command-and-control (C2) communication channels and stop Staem from retrieving secondary stage payloads.",
    "Capture process memory triage to detect and terminate malicious threads injected by Staem into legitimate system processes such as explorer.exe or svchost.exe.",
    "Audit Windows Registry Run keys (HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Run) and Task Scheduler entries to locate and purge Staem persistence hooks.",
    "Deploy updated enterprise EDR detection signatures and conduct an out-of-band endpoint scan to isolate dropped binaries and staged payloads.",
    "Rotate all credentials, domain user passwords, and session cookies active on the system during the Staem execution timeframe."
  ],
  "what_to_avoid": [
    "Do not assume the incident is resolved simply because an antivirus tool removed the initial Staem dropper; always verify that secondary payloads and persistence hooks have been eradicated.",
    "Avoid logging in with Domain Admin or privileged credentials on a machine suspected of running Staem until memory triage is complete.",
    "Do not delay host isolation; automated lateral movement and credential dumping can occur within minutes of initial execution."
  ],
  "target_platforms": [
    "Windows 11",
    "Windows 10",
    "Windows 7"
  ]
}