ET WEB_SPECIFIC_APPS Fortigate Forticlient EMS HTTP Site Header SQL injection attempt (CVE-2026-21643)

Query · suricata

flow:established,to_server;
http.uri;
content:"/api/v1/"; startswith; fast_pattern;
pcre:"/^(?:init_consts|auth\x2fsignin)$/R";
http.header;
content:"Site|3a 20|";
pcre:"/^[^<]*?(?:'|%27|-{2}|%2d%2d)?(?:(?:S(?:HOW.+(?:C(?:UR(?:DAT|TIM)E|HARACTER.+SET)|(?:VARI|T)ABLES)|ELECT.+(?:FROM|USER|SLEEP|CONCAT|CASE))|U(?:NION.+SELEC|PDATE.+SE)T|DELETE.+FROM|INSERT.+INTO)|S(?:HOW.+(?:C(?:HARACTER.+SET|UR(DATE|TIME))|(?:VARI|T)ABLES)|ELECT.+(?:FROM|USER))|U(?:NION.+SELEC|PDATE.+SE)T|(?:NULL(?:\x2c|%2[cC])){2,}|(?:\x2f|%2[fF])(?:\x2a|%2[aA]).+(?:\x2a|%2[aA]).+(?:\x2f|%2[fF])|CONCAT.+SELECT|EXTRACTVALUE|UNION.+ALL)/Ri";
target:dest_ip;
Raw source ET WEB_SPECIFIC_APPS Fortigate Forticlient EMS HTTP Site Header SQL injection attempt (CVE-2026-21643) · Suricata
Esc
Published by Emerging Threats Open ↗, licensed under BSD 3-Clause ↗. Line breaks added for readability; the rule is otherwise unchanged. 
alert http any any -> $HOME_NET any (
    msg:"ET WEB_SPECIFIC_APPS Fortigate Forticlient EMS HTTP Site Header SQL injection attempt (CVE-2026-21643)";
    flow:established,to_server;
    http.uri;
    content:"/api/v1/"; startswith; fast_pattern;
    pcre:"/^(?:init_consts|auth\x2fsignin)$/R";
    http.header;
    content:"Site|3a 20|";
    pcre:"/^[^<]*?(?:'|%27|-{2}|%2d%2d)?(?:(?:S(?:HOW.+(?:C(?:UR(?:DAT|TIM)E|HARACTER.+SET)|(?:VARI|T)ABLES)|ELECT.+(?:FROM|USER|SLEEP|CONCAT|CASE))|U(?:NION.+SELEC|PDATE.+SE)T|DELETE.+FROM|INSERT.+INTO)|S(?:HOW.+(?:C(?:HARACTER.+SET|UR(DATE|TIME))|(?:VARI|T)ABLES)|ELECT.+(?:FROM|USER))|U(?:NION.+SELEC|PDATE.+SE)T|(?:NULL(?:\x2c|%2[cC])){2,}|(?:\x2f|%2[fF])(?:\x2a|%2[aA]).+(?:\x2a|%2[aA]).+(?:\x2f|%2[fF])|CONCAT.+SELECT|EXTRACTVALUE|UNION.+ALL)/Ri";
    reference:cve,2026-21643;
    reference:url,bishopfox.com/blog/cve-2026-21643-pre-authentication-sql-injection-in-forticlient-ems-7-4-4;
    classtype:attempted-admin;
    sid:2068447; rev:1;
    metadata:affected_product FortiClient_EMS, attack_target Server, tls_state plaintext, created_at 2026_03_26, cve CVE_2026_21643, deployment Perimeter, deployment Internal, deployment SSLDecrypt, performance_impact Low, confidence High, signature_severity Major, tag Exploit, updated_at 2026_03_26, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application;
    target:dest_ip;
)

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