27 lines
755 B
Text
27 lines
755 B
Text
rule js_downloader_gootloader : downloader
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{
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meta:
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description = "JavaScript downloader known to deliver Gootkit or REvil ransomware"
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reference = "https://github.com/hpthreatresearch/tools/blob/main/gootloader/js_downloader_gootloader.yar"
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author = "HP Threat Research @HPSecurity"
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filetype = "JavaScript"
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maltype = "Downloader"
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date = "2021-02-22"
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strings:
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$a = "function"
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$b1 = "while"
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$b2 = "if"
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$b3 = "else"
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$b4 = "return"
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$c = "charAt"
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$d = "substr"
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$e1 = "\".+"
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$e2 = "\\=\\\""
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$e3 = " r,"
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$e4 = "+;\\\""
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$f = /(\w+\[\w+\]\s+=\s+\w+\[\w+\[\w+\]\];)/
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condition:
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#a > 8 and #a > (#b4 + 3) and all of ($b*) and ($c or $d) and any of ($e*) and $f and filesize < 8000
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}
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