win_nymaim_auto

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

Detects win.nymaim.

rule win_nymaim_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.nymaim."
        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.nymaim"
        malpedia_rule_date = "20260916"
        malpedia_hash = "53a643781c18e08f4a50949af60172d837a0b6f6"
        malpedia_version = "20260917"
        malpedia_license = "CC BY-SA 4.0"
        malpedia_sharing = "TLP:WHITE"

    


    strings:
        $sequence_0 = { 89d8 01c8 31d2 f7f7 }
                                                            
        $sequence_1 = { 92 31d2 bf64000000 f7f7 }
                                                            
        $sequence_2 = { 09c0 0f94c1 09c8 6bc064 09c0 }
                                                                        
        $sequence_3 = { 31d2 f7f7 92 31d2 }
                                                            
        $sequence_4 = { c1eb13 331d???????? 31c3 c1e808 }
                                                            
        $sequence_5 = { c1e105 01c8 c1c307 30c3 }
                                                            
        $sequence_6 = { 31c9 38f0 83d100 38d0 83d900 c1e105 01c8 }
                                                                                                
        $sequence_7 = { 00d3 8a16 301e 46 01fb }
                                                                        
        $sequence_8 = { c1e808 31c3 895e0c 89d8 }
                                                            
        $sequence_9 = { 8b5514 8b12 8b4d0c 8b5d18 }
                                                            
        $sequence_10 = { f7e0 0fc8 01d0 894704 }
                                                            
        $sequence_11 = { 8b5604 0116 8b4e08 014e04 }
                                                            
        $sequence_12 = { 8b5d18 8b1b 4f 31c0 fec2 }
                                                                        
        $sequence_13 = { 0f854fe70000 448835???????? 015308 395320 0f845a13fdff f6461c20 c705????????8a50d8e8 }
                                                                                                
        $sequence_14 = { 55 89e5 83ec10 8b4508 8d0d3430d201 }
                                                                        
        $sequence_15 = { 890424 894c2404 e8???????? 8d0d3430d201 }
                                                            
        $sequence_16 = { 4189c6 892d???????? 4189f9 4189d8 4489f1 8b8424c8000000 89ea }
                                                                                                
        $sequence_17 = { 5b 5d c3 8b45f0 8b0c850440d201 }
                                                                        
        $sequence_18 = { 448b4d30 4189c3 4531d3 66813d????????65cb 0f8484920200 41f7d1 4531c8 }
                                                                                                
        $sequence_19 = { 48833d????????00 7417 488d4df0 e8???????? 488b9500050000 448b95e0040000 31db }
                                                                                                
        $sequence_20 = { 48813d????????00000050 0f84b243ffff 48c705????????00000000 31ff 4883bba800000000 742b ba20000000 }
                                                                                                
        $sequence_21 = { 56 83ec28 8b450c 8b4d08 8d154e30d201 }
                                                                        
        $sequence_22 = { 31c9 8b55f4 8b75ec 89723c c7424003000000 }
                                                                        
        $sequence_23 = { 4421db 89c2 4409d2 4431ca 4c8d4d40 48ff05???????? 89d1 }
                                                                                                
        $sequence_24 = { 31d2 890c24 c744240400000000 8945f4 8955f0 e8???????? 8d0d8630d201 }
                                                                                                
        $sequence_25 = { 83ec44 8b4508 8d0d2030d201 31d2 890c24 c744240400000000 }
                                                                                    
        $sequence_26 = { 53 56 57 83ec44 8b4508 8d0d2030d201 }
                                                                                    
        $sequence_27 = { 0f876f59feff 488d4c2440 e8???????? e9???????? 4989e3 53 ff0d???????? }
                                                                                                
        $sequence_28 = { 4189c0 895c2420 4189f9 48890d???????? 89f2 89e9 e8???????? }
                                                                                                
    condition:
        1 of them and filesize < 2375680
}

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

c422b9d6-a4ad-4d35-aad8-d47d0cc4ba6f

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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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