win_classfon_auto

YARA detection rule by Felix Bilstein - yara-signator at cocacoding dot com

Detects win.classfon.

rule win_classfon_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.classfon."
        info = "autogenerated rule brought to you by yara-signator"
        tool = "yara-signator v0.6.0"
        signator_config = "callsandjumps;datarefs;binvalue"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.classfon"
        malpedia_rule_date = "20260916"
        malpedia_hash = "53a643781c18e08f4a50949af60172d837a0b6f6"
        malpedia_version = "20260917"
        malpedia_license = "CC BY-SA 4.0"
        malpedia_sharing = "TLP:WHITE"

    


    strings:
        $sequence_0 = { 0f855c010000 8a442424 8d7c2424 84c0 742a 8b1d???????? a1???????? }
                                                                                                
        $sequence_1 = { 89be04020000 8b8600020000 3bc7 740e 83f8ff }
                                                                        
        $sequence_2 = { 57 b985000000 33c0 8d7c240d c644240c00 f3ab 66ab }
                                                                                                
        $sequence_3 = { 53 56 8b35???????? 57 8bbc24dc070000 6800010000 8b07 }
                                                                                                
        $sequence_4 = { 7520 8b4350 6a04 6800200000 }
                                                            
        $sequence_5 = { 6a20 68ff010f00 6a00 8bd0 }
                                                            
        $sequence_6 = { 8bf0 3bf5 0f859d010000 8d4c241c 8d542424 51 8b4c2414 }
                                                                                                
        $sequence_7 = { 683f000f00 6a00 51 52 ff15???????? 8bf0 85f6 }
                                                                                                
        $sequence_8 = { 6a01 6800000080 57 ff15???????? 8b742418 83f8ff }
                                                                                    
        $sequence_9 = { 8b442418 8d4c2400 c744240000000000 51 68???????? }
                                                                        
    condition:
        7 of them and filesize < 73728
}

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

8fe4cd51-d8ee-47b9-8687-0f4e96b6d9a3

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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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