rule win_wannacryptor_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.wannacryptor"
        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 = { 84c0 7505 32c0 c20400 8b542404 }
            // n = 5, score = 600
            //   84c0                 | test                al, al
            //   7505                 | jne                 7
            //   32c0                 | xor                 al, al
            //   c20400               | ret                 4
            //   8b542404             | mov                 edx, dword ptr [esp + 4]

        $sequence_1 = { c7464c17406700 895e54 885e4a 885e4b 8bc6 }
            // n = 5, score = 600
            //   c7464c17406700       | mov                 dword ptr [esi + 0x4c], 0x674017
            //   895e54               | mov                 dword ptr [esi + 0x54], ebx
            //   885e4a               | mov                 byte ptr [esi + 0x4a], bl
            //   885e4b               | mov                 byte ptr [esi + 0x4b], bl
            //   8bc6                 | mov                 eax, esi

        $sequence_2 = { 83ff01 5b 751e 6a01 6a00 }
            // n = 5, score = 600
            //   83ff01               | cmp                 edi, 1
            //   5b                   | pop                 ebx
            //   751e                 | jne                 0x20
            //   6a01                 | push                1
            //   6a00                 | push                0

        $sequence_3 = { 8d4c241c e8???????? 8b4c2418 8b35???????? 51 ffd6 }
            // n = 6, score = 600
            //   8d4c241c             | lea                 ecx, [esp + 0x1c]
            //   e8????????           |                     
            //   8b4c2418             | mov                 ecx, dword ptr [esp + 0x18]
            //   8b35????????         |                     
            //   51                   | push                ecx
            //   ffd6                 | call                esi

        $sequence_4 = { 8b842488000000 8d542474 52 50 ff15???????? 33c0 }
            // n = 6, score = 600
            //   8b842488000000       | mov                 eax, dword ptr [esp + 0x88]
            //   8d542474             | lea                 edx, [esp + 0x74]
            //   52                   | push                edx
            //   50                   | push                eax
            //   ff15????????         |                     
            //   33c0                 | xor                 eax, eax

        $sequence_5 = { 8d7e44 8b48f8 8b4674 3bc8 7d16 2bc1 }
            // n = 6, score = 600
            //   8d7e44               | lea                 edi, [esi + 0x44]
            //   8b48f8               | mov                 ecx, dword ptr [eax - 8]
            //   8b4674               | mov                 eax, dword ptr [esi + 0x74]
            //   3bc8                 | cmp                 ecx, eax
            //   7d16                 | jge                 0x18
            //   2bc1                 | sub                 eax, ecx

        $sequence_6 = { e8???????? 83c404 8b03 c74304ffffffff }
            // n = 4, score = 600
            //   e8????????           |                     
            //   83c404               | add                 esp, 4
            //   8b03                 | mov                 eax, dword ptr [ebx]
            //   c74304ffffffff       | mov                 dword ptr [ebx + 4], 0xffffffff

        $sequence_7 = { 83c408 85c0 7513 6800400000 e8???????? 83c404 89833c010000 }
            // n = 7, score = 600
            //   83c408               | add                 esp, 8
            //   85c0                 | test                eax, eax
            //   7513                 | jne                 0x15
            //   6800400000           | push                0x4000
            //   e8????????           |                     
            //   83c404               | add                 esp, 4
            //   89833c010000         | mov                 dword ptr [ebx + 0x13c], eax

        $sequence_8 = { 03f9 4b 75dd eb4f 83f801 754a }
            // n = 6, score = 600
            //   03f9                 | add                 edi, ecx
            //   4b                   | dec                 ebx
            //   75dd                 | jne                 0xffffffdf
            //   eb4f                 | jmp                 0x51
            //   83f801               | cmp                 eax, 1
            //   754a                 | jne                 0x4c

        $sequence_9 = { 894204 8b4e0c 3bcb 741e 8a41ff 3ac3 }
            // n = 6, score = 600
            //   894204               | mov                 dword ptr [edx + 4], eax
            //   8b4e0c               | mov                 ecx, dword ptr [esi + 0xc]
            //   3bcb                 | cmp                 ecx, ebx
            //   741e                 | je                  0x20
            //   8a41ff               | mov                 al, byte ptr [ecx - 1]
            //   3ac3                 | cmp                 al, bl

    condition:
        7 of them and filesize < 540672
}