Rule History

SID: 2043353 • Source: et/open

Versions (5)

Version DetailsCurrent

Rev: 1 • Jan 19, 2023, 12:00 PM

Message:

ET MALWARE Observed BatLoader Domain (grammarlycheck2 .com) in TLS SNI

Rule:

alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed BatLoader Domain (grammarlycheck2 .com) in TLS SNI"; flow:established,to_server; tls.sni; content:"grammarlycheck2.com"; bsize:19; fast_pattern; reference:url,www.trendmicro.com/en_us/research/23/a/batloader-malware-abuses-legitimate-tools-uses-obfuscated-javasc.html; classtype:domain-c2; sid:2043353; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2023_01_19, deployment Perimeter, malware_family BatLoader, performance_impact Low, confidence High, signature_severity Major, updated_at 2023_01_19, reviewed_at 2025_07_14;)

Created:

Jan 19, 2023, 12:00 PM

Updated:

Jan 19, 2023, 12:00 PM

DB Created:

Sep 21, 2024, 3:00 AM

DB Updated:

Jul 14, 2025, 9:34 PM

Filename:

rules/emerging-malware.rules