win_ryuk_auto

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

Detects win.ryuk.

rule win_ryuk_auto {

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

    


    strings:
        $sequence_0 = { 68???????? 6a01 6a00 6814010000 }
                                                            
        $sequence_1 = { 85c0 7508 6a01 ff15???????? 68???????? 6a01 }
                                                                                    
        $sequence_2 = { 6a08 6a18 68???????? 68???????? 68???????? ff15???????? 85c0 }
                                                                                                
        $sequence_3 = { 754c b90b010000 66398818000035 753e 8b4508 }
                                                                        
        $sequence_4 = { 68???????? ff15???????? 85c0 7578 6a10 6a18 68???????? }
                                                                                                
        $sequence_5 = { 68c0cf6a00 ff15???????? 6a01 ff15???????? }
                                                            
        $sequence_6 = { e8???????? 68e8030000 ff15???????? 68???????? e8???????? }
                                                                        
        $sequence_7 = { 85c0 7407 b801000000 eb0b eb04 33c0 eb05 }
                                                                                                
        $sequence_8 = { 6bd100 8b4dfc 880411 ba04000000 }
                                                            
        $sequence_9 = { 0fb60c10 83c101 ba01000000 d1e2 8b45fc }
                                                                        
        $sequence_10 = { 0345f4 1355f8 8945f4 8955f8 837d0800 }
                                                                        
        $sequence_11 = { 50 8b0d???????? 51 6a01 68???????? e8???????? }
                                                                                    
        $sequence_12 = { 0f870b020000 720c 8b459c 3b45f4 0f87fd010000 b904000000 }
                                                                                    
        $sequence_13 = { ff15???????? b811000000 e9???????? e9???????? }
                                                            
        $sequence_14 = { 7407 48 85c0 7ff0 }
                                                            
        $sequence_15 = { ff35???????? ff15???????? 833d????????00 6a10 6a18 }
                                                                        
        $sequence_16 = { 6a00 6814010000 ff7508 ff35???????? }
                                                            
        $sequence_17 = { 2bf0 33c0 66890473 83ffff }
                                                            
        $sequence_18 = { ff15???????? b803000000 eb05 b805000000 }
                                                            
        $sequence_19 = { 751b ff35???????? ff35???????? 6a01 68???????? e8???????? }
                                                                                    
        $sequence_20 = { 85d2 7714 7212 81f9d0070000 770a 85d2 }
                                                                                    
        $sequence_21 = { 56 ff15???????? 8bcb 8d5102 }
                                                            
        $sequence_22 = { eb0b 8bc1 99 f7fe }
                                                            
        $sequence_23 = { 2bf2 68???????? 53 d1fe e8???????? 83c408 }
                                                                                    
        $sequence_24 = { 0f9fc0 5d c3 8bff 55 8bec 8b4508 }
                                                                                                
        $sequence_25 = { 8d7f02 6685c0 75f4 a1???????? 8907 eb03 }
                                                                                    
        $sequence_26 = { 83c602 6685c9 75f5 2bf2 68???????? 53 }
                                                                                    
        $sequence_27 = { 66f3ab 488b7c2408 498bc1 c3 4053 4883ec20 8bc1 }
                                                                                                
        $sequence_28 = { 4983c8ff e8???????? 488bc3 4883c430 5b c3 48895c2408 }
                                                                                                
        $sequence_29 = { 83e103 f3a4 8d7afe 668b4702 8d7f02 6685c0 }
                                                                                    
        $sequence_30 = { 4883c428 c3 48895c2408 57 4883ec30 8364242000 }
                                                                                    
        $sequence_31 = { 6685c0 75f5 8d7bfe 2bd6 8d5f02 668b4702 83c702 }
                                                                                                
        $sequence_32 = { 2bca 33c0 6689444bfe e9???????? }
                                                            
        $sequence_33 = { e8???????? 99 2bc2 d1f8 85c0 }
                                                                        
        $sequence_34 = { 33c9 ff15???????? 448b442468 33d2 }
                                                            
        $sequence_35 = { 66837f0254 750f 66837f0641 7508 }
                                                            
        $sequence_36 = { ff15???????? 83f820 7510 488bcb ff15???????? b802000000 }
                                                                                    
        $sequence_37 = { e8???????? 488bcf ff15???????? 8d4301 e9???????? }
                                                                        
        $sequence_38 = { ff15???????? 66833f4e 7516 66837f0254 }
                                                            
        $sequence_39 = { ff15???????? 41b900300000 c744242040000000 448bc3 }
                                                            
        $sequence_40 = { 48897c2430 488d4c2440 c744242802000000 4533c9 4533c0 }
                                                                        
        $sequence_41 = { 8905???????? e8???????? b988130000 8bd8 }
                                                            
        $sequence_42 = { 8bc1 2bc2 d1e8 03c2 c1e806 6bc05a }
                                                                                    
        $sequence_43 = { c744242003000000 ba00000040 ff15???????? 488bd8 ff15???????? }
                                                                        
        $sequence_44 = { 8903 e8???????? 84c0 746c e8???????? 488d0d63080000 e8???????? }
                                                                                                
        $sequence_45 = { 488d0d63080000 e8???????? e8???????? 8bc8 e8???????? 85c0 7556 }
                                                                                                
    condition:
        7 of them and filesize < 7450624
}

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

0a421d9f-dc55-4d2f-926b-dad9156399d2

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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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