msil_suspicious_use_of_strreverse

YARA detection rule by dr4k0nia · NOASSERTION

Detects mixed use of Microsoft.CSharp and VisualBasic to use StrReverse

import "dotnet"
rule msil_suspicious_use_of_strreverse {
    meta:
        
        description = "Detects mixed use of Microsoft.CSharp and VisualBasic to use StrReverse"
        author = "dr4k0nia"
        version = "1.1"
        date = "01/31/2023"
        modified = "02/22/2023"
        hash = "02ce0980427dea835fc9d9eed025dd26672bf2c15f0b10486ff8107ce3950701"
    strings:
        $csharp = "Microsoft.CSharp"
        $vbnet = "Microsoft.VisualBasic"
        $strreverse = "StrReverse"
    condition:
        uint16(0) == 0x5a4d
        and dotnet.is_dotnet
        and filesize < 50MB
        and $csharp
        and $vbnet
        and $strreverse
}

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

3ca6055f-ece9-4185-9e86-446cf1a1b44d

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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 ]]

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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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