TextShell

YARA detection rule by RussianPanda

Detects TextShell Obfsucator

rule TextShell {
    meta:
        description = "Detects TextShell Obfsucator"
        author = "RussianPanda"
        date = "2025-10-31"
        hash = "cf44aa11a17b3dad61cae715f4ea27c0cbf80732a1a7a1c530a5c9d3d183482a"
    strings:
        $s1 = {41 8B 04 84 48 03 ?? EB}
        $s2 = {41 3B ?? 74 ?? FF C3 3B 5D 18 72}
        $s3 = {FF 15 ?? ?? ?? ?? 48 8B}
    condition:
        uint16(0) == 0x5A4D and all of them and #s3 > 1000
}

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

11354fee-62ee-4e4c-a52f-2b923d04236c

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Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

[[ reason ]]

What does this mean?

Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

[[ reason ]]

What do these messages mean?

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

[[ currentRule.title ]]

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