ET MALWARE Win32/Atomsilo Ransomware Activity (POST)

Query · suricata

flow:established,to_server;
http.method;
content:"POST";
http.uri;
content:".php"; endswith;
http.user_agent;
content:"Microsoft"; bsize:9;
http.request_body;
content:"blocknum="; startswith; fast_pattern;
content:"&computername="; distance:0;
content:"&base64privkey="; distance:0;
content:"&base64pubkey="; distance:0;
Raw source ET MALWARE Win32/Atomsilo Ransomware Activity (POST) · Suricata
Esc
Published by Emerging Threats Open ↗, licensed under BSD 3-Clause ↗. Line breaks added for readability; the rule is otherwise unchanged. 
alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"ET MALWARE Win32/Atomsilo Ransomware Activity (POST)";
    flow:established,to_server;
    http.method;
    content:"POST";
    http.uri;
    content:".php"; endswith;
    http.user_agent;
    content:"Microsoft"; bsize:9;
    http.request_body;
    content:"blocknum="; startswith; fast_pattern;
    content:"&computername="; distance:0;
    content:"&base64privkey="; distance:0;
    content:"&base64pubkey="; distance:0;
    reference:md5,17b447b971a4977b2bfb2c28659aa1dd;
    reference:url,www.sentinelone.com/blog/living-off-windows-defender-lockbit-ransomware-sideloads-cobalt-strike-through-microsoft-security-tool/;
    classtype:trojan-activity;
    sid:2038577; rev:1;
    metadata:attack_target Client_Endpoint, created_at 2022_08_22, deployment Perimeter, malware_family LockBit, malware_family AtomSilo, confidence High, signature_severity Major, tag Ransomware, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_08_22, mitre_tactic_id TA0040, mitre_tactic_name Impact, mitre_technique_id T1486, mitre_technique_name Data_Encrypted_for_Impact;
)

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