rule win_ryuk_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2020-05-30"
        version = "1"
        description = "autogenerated rule brought to you by yara-signator"
        tool = "yara-signator v0.4.0"
        tool_config = "callsandjumps;datarefs;binvalue"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.ryuk"
        malpedia_rule_date = "20200529"
        malpedia_hash = "92c362319514e5a6da26204961446caa3a8b32a8"
        malpedia_version = "20200529"
        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 is published 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 = { ff15???????? b803000000 eb05 b805000000 }
            // n = 4, score = 800
            //   ff15????????         |                     
            //   b803000000           | mov                 eax, 3
            //   eb05                 | jmp                 7
            //   b805000000           | mov                 eax, 5

        $sequence_1 = { 68???????? 6a01 6a00 6814010000 }
            // n = 4, score = 800
            //   68????????           |                     
            //   6a01                 | push                1
            //   6a00                 | push                0
            //   6814010000           | push                0x114

        $sequence_2 = { e8???????? e8???????? b9e8030000 ff15???????? }
            // n = 4, score = 700
            //   e8????????           |                     
            //   e8????????           |                     
            //   b9e8030000           | mov                 ecx, 0x3e8
            //   ff15????????         |                     

        $sequence_3 = { 85c0 7508 6a01 ff15???????? 68???????? }
            // n = 5, score = 700
            //   85c0                 | test                eax, eax
            //   7508                 | jne                 0xa
            //   6a01                 | push                1
            //   ff15????????         |                     
            //   68????????           |                     

        $sequence_4 = { 4983c8ff e8???????? 488bc3 4883c430 5b c3 48895c2408 }
            // n = 7, score = 600
            //   4983c8ff             | inc                 ebp
            //   e8????????           |                     
            //   488bc3               | xor                 ecx, ecx
            //   4883c430             | inc                 ebp
            //   5b                   | xor                 eax, eax
            //   c3                   | dec                 eax
            //   48895c2408           | add                 esp, 0x28

        $sequence_5 = { 0f9fc0 5d c3 8bff 55 8bec 8b4508 }
            // n = 7, score = 600
            //   0f9fc0               | setg                al
            //   5d                   | pop                 ebp
            //   c3                   | ret                 
            //   8bff                 | mov                 edi, edi
            //   55                   | push                ebp
            //   8bec                 | mov                 ebp, esp
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]

        $sequence_6 = { ff7508 e8???????? 5e 5d c3 6a08 }
            // n = 6, score = 600
            //   ff7508               | push                dword ptr [ebp + 8]
            //   e8????????           |                     
            //   5e                   | pop                 esi
            //   5d                   | pop                 ebp
            //   c3                   | ret                 
            //   6a08                 | push                8

        $sequence_7 = { b809000000 e9???????? 4533c9 4533c0 33d2 }
            // n = 5, score = 600
            //   b809000000           | mov                 eax, 9
            //   e9????????           |                     
            //   4533c9               | inc                 ebp
            //   4533c0               | xor                 ecx, ecx
            //   33d2                 | inc                 ebp

        $sequence_8 = { 498bc1 c3 4053 4883ec20 8bc1 498bd8 }
            // n = 6, score = 600
            //   498bc1               | inc                 ebp
            //   c3                   | xor                 ecx, ecx
            //   4053                 | inc                 ebp
            //   4883ec20             | xor                 eax, eax
            //   8bc1                 | dec                 ecx
            //   498bd8               | mov                 eax, ecx

        $sequence_9 = { 0fb7c1 498bc8 66f3ab 488b7c2408 498bc1 c3 4053 }
            // n = 7, score = 600
            //   0fb7c1               | xor                 ecx, ecx
            //   498bc8               | dec                 eax
            //   66f3ab               | mov                 eax, ebx
            //   488b7c2408           | dec                 eax
            //   498bc1               | add                 esp, 0x30
            //   c3                   | pop                 ebx
            //   4053                 | ret                 

        $sequence_10 = { 8d7602 6685c9 75f1 5e 5d c3 8bff }
            // n = 7, score = 600
            //   8d7602               | lea                 esi, [esi + 2]
            //   6685c9               | test                cx, cx
            //   75f1                 | jne                 0xfffffff3
            //   5e                   | pop                 esi
            //   5d                   | pop                 ebp
            //   c3                   | ret                 
            //   8bff                 | mov                 edi, edi

        $sequence_11 = { c20400 8bff 55 8bec b8ffff0000 83ec18 }
            // n = 6, score = 600
            //   c20400               | ret                 4
            //   8bff                 | mov                 edi, edi
            //   55                   | push                ebp
            //   8bec                 | mov                 ebp, esp
            //   b8ffff0000           | mov                 eax, 0xffff
            //   83ec18               | sub                 esp, 0x18

        $sequence_12 = { 4883c428 c3 48895c2408 57 4883ec30 8364242000 }
            // n = 6, score = 600
            //   4883c428             | dec                 eax
            //   c3                   | sub                 esp, 0x20
            //   48895c2408           | mov                 eax, ecx
            //   57                   | dec                 ecx
            //   4883ec30             | mov                 ebx, eax
            //   8364242000           | mov                 eax, 9

        $sequence_13 = { 7423 8078ff48 751d 803845 7518 80780152 7512 }
            // n = 7, score = 500
            //   7423                 | inc                 eax
            //   8078ff48             | push                ebx
            //   751d                 | dec                 eax
            //   803845               | sub                 esp, 0x20
            //   7518                 | mov                 eax, ecx
            //   80780152             | dec                 ecx
            //   7512                 | mov                 ebx, eax

        $sequence_14 = { 4533c9 4533c0 c744242003000000 ba00000040 }
            // n = 4, score = 500
            //   4533c9               | mov                 ecx, 0x3e8
            //   4533c0               | ret                 
            //   c744242003000000     | dec                 eax
            //   ba00000040           | mov                 dword ptr [esp + 8], ebx

        $sequence_15 = { ff15???????? 85c0 750a b804000000 e9???????? }
            // n = 5, score = 500
            //   ff15????????         |                     
            //   85c0                 | dec                 ecx
            //   750a                 | mov                 eax, ecx
            //   b804000000           | ret                 
            //   e9????????           |                     

        $sequence_16 = { e9???????? 6a04 6800100000 6810270000 }
            // n = 4, score = 500
            //   e9????????           |                     
            //   6a04                 | push                4
            //   6800100000           | push                0x1000
            //   6810270000           | push                0x2710

        $sequence_17 = { c744242802000000 4533c9 4533c0 c744242002000000 ba000000c0 }
            // n = 5, score = 500
            //   c744242802000000     | push                edi
            //   4533c9               | push                ebx
            //   4533c0               | test                eax, eax
            //   c744242002000000     | jne                 0x56
            //   ba000000c0           | push                0x10

        $sequence_18 = { 8bc1 2bc2 d1e8 03c2 c1e806 6bc05a }
            // n = 6, score = 500
            //   8bc1                 | mov                 dword ptr [esp + 8], ebx
            //   2bc2                 | dec                 eax
            //   d1e8                 | mov                 dword ptr [esp + 0x10], ebp
            //   03c2                 | rep stosd           dword ptr es:[edi], eax
            //   c1e806               | dec                 eax
            //   6bc05a               | mov                 edi, dword ptr [esp + 8]

        $sequence_19 = { 7407 48 85c0 7ff0 }
            // n = 4, score = 500
            //   7407                 | je                  9
            //   48                   | dec                 eax
            //   85c0                 | test                eax, eax
            //   7ff0                 | jg                  0xfffffff2

        $sequence_20 = { 488bcf ff15???????? 41b900800000 4533c0 488bd6 488bcf }
            // n = 6, score = 500
            //   488bcf               | xor                 ecx, ecx
            //   ff15????????         |                     
            //   41b900800000         | mov                 eax, 9
            //   4533c0               | inc                 ebp
            //   488bd6               | xor                 ecx, ecx
            //   488bcf               | inc                 ebp

        $sequence_21 = { 8b5c3050 ff15???????? 41b900300000 c744242040000000 448bc3 488bd6 }
            // n = 6, score = 500
            //   8b5c3050             | push                esi
            //   ff15????????         |                     
            //   41b900300000         | push                edi
            //   c744242040000000     | mov                 eax, 3
            //   448bc3               | jmp                 7
            //   488bd6               | mov                 eax, 5

        $sequence_22 = { 53 6a28 ffd6 50 }
            // n = 4, score = 400
            //   53                   | push                ebx
            //   6a28                 | push                0x28
            //   ffd6                 | call                esi
            //   50                   | push                eax

        $sequence_23 = { 33f6 56 56 ff15???????? 6800800000 56 57 }
            // n = 7, score = 400
            //   33f6                 | xor                 esi, esi
            //   56                   | push                esi
            //   56                   | push                esi
            //   ff15????????         |                     
            //   6800800000           | push                0x8000
            //   56                   | push                esi
            //   57                   | push                edi

        $sequence_24 = { 7407 b801000000 eb0b eb04 }
            // n = 4, score = 400
            //   7407                 | ret                 
            //   b801000000           | inc                 eax
            //   eb0b                 | push                ebx
            //   eb04                 | dec                 eax

        $sequence_25 = { 6a08 6a18 68???????? 68???????? 68???????? ff15???????? }
            // n = 6, score = 400
            //   6a08                 | push                8
            //   6a18                 | push                0x18
            //   68????????           |                     
            //   68????????           |                     
            //   68????????           |                     
            //   ff15????????         |                     

        $sequence_26 = { 57 53 ff15???????? 85c0 7554 6a10 }
            // n = 6, score = 400
            //   57                   | push                edi
            //   53                   | push                ebx
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   7554                 | jne                 0x56
            //   6a10                 | push                0x10

        $sequence_27 = { 6a00 ff15???????? 6a00 6a02 6a03 }
            // n = 5, score = 400
            //   6a00                 | mul                 ecx
            //   ff15????????         |                     
            //   6a00                 | mov                 eax, ecx
            //   6a02                 | sub                 eax, edx
            //   6a03                 | shr                 eax, 1

        $sequence_28 = { 7568 6a28 56 68???????? 57 53 ff15???????? }
            // n = 7, score = 400
            //   7568                 | jne                 0x6a
            //   6a28                 | push                0x28
            //   56                   | push                esi
            //   68????????           |                     
            //   57                   | push                edi
            //   53                   | push                ebx
            //   ff15????????         |                     

        $sequence_29 = { e8???????? 83c404 33c9 8b5508 66894c42e2 8b45fc }
            // n = 6, score = 300
            //   e8????????           |                     
            //   83c404               | pop                 esi
            //   33c9                 | pop                 ebp
            //   8b5508               | ret                 
            //   66894c42e2           | push                8
            //   8b45fc               | ret                 4

        $sequence_30 = { 57 ff15???????? b80c000000 5f }
            // n = 4, score = 200
            //   57                   | push                edi
            //   ff15????????         |                     
            //   b80c000000           | mov                 eax, 0xc
            //   5f                   | pop                 edi

        $sequence_31 = { 6a0a c1e818 51 50 }
            // n = 4, score = 200
            //   6a0a                 | push                0xa
            //   c1e818               | shr                 eax, 0x18
            //   51                   | push                ecx
            //   50                   | push                eax

        $sequence_32 = { 51 6a00 ffd6 6800400000 6a40 }
            // n = 5, score = 200
            //   51                   | push                ecx
            //   6a00                 | push                0
            //   ffd6                 | call                esi
            //   6800400000           | push                0x4000
            //   6a40                 | push                0x40

        $sequence_33 = { 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_34 = { 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_35 = { ff15???????? b80f000000 5f 5e }
            // n = 4, score = 200
            //   ff15????????         |                     
            //   b80f000000           | mov                 eax, 0xf
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi

        $sequence_36 = { ff7004 ff30 e8???????? 68???????? 8d442410 c744241058234300 50 }
            // n = 7, score = 100
            //   ff7004               | push                dword ptr [eax + 4]
            //   ff30                 | push                dword ptr [eax]
            //   e8????????           |                     
            //   68????????           |                     
            //   8d442410             | lea                 eax, [esp + 0x10]
            //   c744241058234300     | mov                 dword ptr [esp + 0x10], 0x432358
            //   50                   | push                eax

        $sequence_37 = { c78540fdffff00000000 ff15???????? 8d856cfdffff 50 56 }
            // n = 5, score = 100
            //   c78540fdffff00000000     | mov    dword ptr [ebp - 0x2c0], 0
            //   ff15????????         |                     
            //   8d856cfdffff         | lea                 eax, [ebp - 0x294]
            //   50                   | push                eax
            //   56                   | push                esi

    condition:
        7 of them and filesize < 7450624
}