rule win_ryuk_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2019-11-26"
        version = "1"
        description = "autogenerated rule brought to you by yara-signator"
        tool = "yara-signator 0.1a"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.ryuk"
        malpedia_version = "20190204"
        malpedia_license = "CC BY-NC-SA 4.0"
        malpedia_sharing = "TLP:WHITE"

    /* DISCLAIMER
     * The strings used in this rule have been automatically selected from the
     * disassembly of memory dumps and unpacked files, using yara-signator.
     * The code and documentation / approach will be published in the near future here:
     * https://github.com/fxb-cocacoding/yara-signator
     * As Malpedia is used as data source, please note that for a given
     * number of families, only single samples are documented.
     * This likely impacts the degree of generalization these rules will offer.
     * Take the described generation method also into consideration when you
     * apply the rules in your use cases and assign them confidence levels.
     */

    strings:
        $sequence_0 = { c3 4053 4883ec20 8bc1 498bd8 33c9 4c8bda }
            // n = 7, score = 600
            //   c3                   | dec                 eax
            //   4053                 | mov                 eax, ebx
            //   4883ec20             | dec                 eax
            //   8bc1                 | add                 esp, 0x30
            //   498bd8               | pop                 ebx
            //   33c9                 | ret                 
            //   4c8bda               | dec                 eax

        $sequence_1 = { 415e c3 4053 4883ec20 488bd9 33c9 48890b }
            // n = 7, score = 600
            //   415e                 | mov                 dword ptr [esp + 8], ebx
            //   c3                   | dec                 eax
            //   4053                 | mov                 dword ptr [esp + 0x10], ebp
            //   4883ec20             | ret                 
            //   488bd9               | inc                 eax
            //   33c9                 | push                ebx
            //   48890b               | dec                 eax

        $sequence_2 = { ff15???????? b803000000 eb05 b805000000 }
            // n = 4, score = 600
            //   ff15????????         |                     
            //   b803000000           | sub                 esp, 0x20
            //   eb05                 | mov                 eax, ecx
            //   b805000000           | dec                 ecx

        $sequence_3 = { 4983c8ff e8???????? 488bc3 4883c430 5b c3 48895c2408 }
            // n = 7, score = 600
            //   4983c8ff             | dec                 ecx
            //   e8????????           |                     
            //   488bc3               | or                  eax, 0xffffffff
            //   4883c430             | dec                 eax
            //   5b                   | mov                 eax, ebx
            //   c3                   | dec                 eax
            //   48895c2408           | add                 esp, 0x30

        $sequence_4 = { e8???????? e8???????? b9e8030000 ff15???????? }
            // n = 4, score = 600
            //   e8????????           |                     
            //   e8????????           |                     
            //   b9e8030000           | jmp                 0xc
            //   ff15????????         |                     

        $sequence_5 = { b809000000 e9???????? 4533c9 4533c0 }
            // n = 4, score = 600
            //   b809000000           | pop                 ebx
            //   e9????????           |                     
            //   4533c9               | ret                 
            //   4533c0               | dec                 eax

        $sequence_6 = { 4c8d05???????? 488d15???????? 488d0d???????? ff15???????? 85c0 }
            // n = 5, score = 600
            //   4c8d05????????       |                     
            //   488d15????????       |                     
            //   488d0d????????       |                     
            //   ff15????????         |                     
            //   85c0                 | dec                 eax

        $sequence_7 = { eb04 4883c020 4883c428 c3 48895c2408 57 4883ec30 }
            // n = 7, score = 600
            //   eb04                 | inc                 eax
            //   4883c020             | push                ebx
            //   4883c428             | dec                 eax
            //   c3                   | sub                 esp, 0x20
            //   48895c2408           | mov                 eax, ecx
            //   57                   | dec                 ecx
            //   4883ec30             | mov                 ebx, eax

        $sequence_8 = { 50 e8???????? 50 57 6800000030 e8???????? }
            // n = 6, score = 400
            //   50                   | push                eax
            //   e8????????           |                     
            //   50                   | push                eax
            //   57                   | push                edi
            //   6800000030           | push                0x30000000
            //   e8????????           |                     

        $sequence_9 = { 6800000030 e8???????? 83c408 85c0 }
            // n = 4, score = 400
            //   6800000030           | push                0x30000000
            //   e8????????           |                     
            //   83c408               | add                 esp, 8
            //   85c0                 | test                eax, eax

        $sequence_10 = { b900000030 2bc1 50 51 e8???????? 59 }
            // n = 6, score = 400
            //   b900000030           | mov                 ecx, 0x30000000
            //   2bc1                 | sub                 eax, ecx
            //   50                   | push                eax
            //   51                   | push                ecx
            //   e8????????           |                     
            //   59                   | pop                 ecx

        $sequence_11 = { 8b4508 2d00000030 50 6800000030 e8???????? }
            // n = 5, score = 400
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   2d00000030           | sub                 eax, 0x30000000
            //   50                   | push                eax
            //   6800000030           | push                0x30000000
            //   e8????????           |                     

        $sequence_12 = { 8d45f0 64a300000000 8965e8 c745fc00000000 6800000030 }
            // n = 5, score = 400
            //   8d45f0               | lea                 eax, [ebp - 0x10]
            //   64a300000000         | mov                 dword ptr fs:[0], eax
            //   8965e8               | mov                 dword ptr [ebp - 0x18], esp
            //   c745fc00000000       | mov                 dword ptr [ebp - 4], 0
            //   6800000030           | push                0x30000000

        $sequence_13 = { c745fc00000000 6800000030 e8???????? 83c404 85c0 7454 8b4508 }
            // n = 7, score = 400
            //   c745fc00000000       | mov                 dword ptr [ebp - 4], 0
            //   6800000030           | push                0x30000000
            //   e8????????           |                     
            //   83c404               | add                 esp, 4
            //   85c0                 | test                eax, eax
            //   7454                 | je                  0x56
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]

        $sequence_14 = { 6823110030 51 e8???????? 8bf0 }
            // n = 4, score = 300
            //   6823110030           | push                0x30001123
            //   51                   | push                ecx
            //   e8????????           |                     
            //   8bf0                 | mov                 esi, eax

        $sequence_15 = { 754f b90b010000 66398818000030 7541 8b4508 b900000030 2bc1 }
            // n = 7, score = 300
            //   754f                 | jne                 0x51
            //   b90b010000           | mov                 ecx, 0x10b
            //   66398818000030       | cmp                 word ptr [eax + 0x30000018], cx
            //   7541                 | jne                 0x43
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   b900000030           | mov                 ecx, 0x30000000
            //   2bc1                 | sub                 eax, ecx

        $sequence_16 = { 8d0c49 c1e103 51 6a00 }
            // n = 4, score = 200
            //   8d0c49               | lea                 ecx, [ecx + ecx*2]
            //   c1e103               | shl                 ecx, 3
            //   51                   | push                ecx
            //   6a00                 | push                0

        $sequence_17 = { 6a00 ffd6 6800400000 6a40 }
            // n = 4, score = 200
            //   6a00                 | push                0
            //   ffd6                 | call                esi
            //   6800400000           | push                0x4000
            //   6a40                 | push                0x40

        $sequence_18 = { 57 ff15???????? b80c000000 5f }
            // n = 4, score = 200
            //   57                   | push                edi
            //   ff15????????         |                     
            //   b80c000000           | mov                 eax, 0xc
            //   5f                   | pop                 edi

        $sequence_19 = { 2bf0 33c0 66890473 83ffff }
            // n = 4, score = 200
            //   2bf0                 | sub                 esi, eax
            //   33c0                 | xor                 eax, eax
            //   66890473             | mov                 word ptr [ebx + esi*2], ax
            //   83ffff               | cmp                 edi, -1

        $sequence_20 = { 6a00 ff15???????? 6a00 6a02 6a03 6a00 }
            // n = 6, score = 200
            //   6a00                 | sub                 eax, ecx
            //   ff15????????         |                     
            //   6a00                 | push                eax
            //   6a02                 | push                ecx
            //   6a03                 | add                 esp, 4
            //   6a00                 | test                eax, eax

        $sequence_21 = { c20400 8bff 55 8bec b8ffff0000 83ec18 }
            // n = 6, score = 200
            //   c20400               | push                eax
            //   8bff                 | push                ecx
            //   55                   | mov                 eax, dword ptr [ebp + 8]
            //   8bec                 | mov                 ecx, 0x30000000
            //   b8ffff0000           | sub                 eax, ecx
            //   83ec18               | push                eax

        $sequence_22 = { 6a0a c1e818 51 50 }
            // n = 4, score = 200
            //   6a0a                 | push                0xa
            //   c1e818               | shr                 eax, 0x18
            //   51                   | push                ecx
            //   50                   | push                eax

        $sequence_23 = { ff15???????? b808000000 5f 5e }
            // n = 4, score = 200
            //   ff15????????         |                     
            //   b808000000           | mov                 eax, 8
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi

        $sequence_24 = { 7e19 ff734c 4e 0fbe0406 }
            // n = 4, score = 100
            //   7e19                 | jle                 0x1b
            //   ff734c               | push                dword ptr [ebx + 0x4c]
            //   4e                   | dec                 esi
            //   0fbe0406             | movsx               eax, byte ptr [esi + eax]

        $sequence_25 = { 0f849e000000 833e00 0f8595000000 6a44 e8???????? }
            // n = 5, score = 100
            //   0f849e000000         | je                  0xa4
            //   833e00               | cmp                 dword ptr [esi], 0
            //   0f8595000000         | jne                 0x9b
            //   6a44                 | push                0x44
            //   e8????????           |                     

    condition:
        7 of them
}