rule win_wannacryptor_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2020-10-14"
        version = "1"
        description = "autogenerated rule brought to you by yara-signator"
        tool = "yara-signator v0.5.0"
        tool_config = "callsandjumps;datarefs;binvalue"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.wannacryptor"
        malpedia_rule_date = "20201014"
        malpedia_hash = "a7e3bd57eaf12bf3ea29a863c041091ba3af9ac9"
        malpedia_version = "20201014"
        malpedia_license = "CC BY-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 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 = { 0f8c41010000 807c241405 0f8536010000 0fbe542415 81faff000000 0f8425010000 }
            // n = 6, score = 600
            //   0f8c41010000         | jl                  0x147
            //   807c241405           | cmp                 byte ptr [esp + 0x14], 5
            //   0f8536010000         | jne                 0x13c
            //   0fbe542415           | movsx               edx, byte ptr [esp + 0x15]
            //   81faff000000         | cmp                 edx, 0xff
            //   0f8425010000         | je                  0x12b

        $sequence_1 = { c644241000 7423 8bfb 83c9ff }
            // n = 4, score = 600
            //   c644241000           | mov                 byte ptr [esp + 0x10], 0
            //   7423                 | je                  0x25
            //   8bfb                 | mov                 edi, ebx
            //   83c9ff               | or                  ecx, 0xffffffff

        $sequence_2 = { 85db 0f84ad010000 8b4e68 8b463c 8b5660 03c8 6a00 }
            // n = 7, score = 600
            //   85db                 | test                ebx, ebx
            //   0f84ad010000         | je                  0x1b3
            //   8b4e68               | mov                 ecx, dword ptr [esi + 0x68]
            //   8b463c               | mov                 eax, dword ptr [esi + 0x3c]
            //   8b5660               | mov                 edx, dword ptr [esi + 0x60]
            //   03c8                 | add                 ecx, eax
            //   6a00                 | push                0

        $sequence_3 = { e8???????? 50 8bcf c644243407 e8???????? 8d4c241c 885c2430 }
            // n = 7, score = 600
            //   e8????????           |                     
            //   50                   | push                eax
            //   8bcf                 | mov                 ecx, edi
            //   c644243407           | mov                 byte ptr [esp + 0x34], 7
            //   e8????????           |                     
            //   8d4c241c             | lea                 ecx, [esp + 0x1c]
            //   885c2430             | mov                 byte ptr [esp + 0x30], bl

        $sequence_4 = { 8b742418 83ff01 5b 751e 6a01 6a00 6a00 }
            // n = 7, score = 600
            //   8b742418             | mov                 esi, dword ptr [esp + 0x18]
            //   83ff01               | cmp                 edi, 1
            //   5b                   | pop                 ebx
            //   751e                 | jne                 0x20
            //   6a01                 | push                1
            //   6a00                 | push                0
            //   6a00                 | push                0

        $sequence_5 = { 83fa01 0f850f010000 38564b 7526 8b4644 }
            // n = 5, score = 600
            //   83fa01               | cmp                 edx, 1
            //   0f850f010000         | jne                 0x115
            //   38564b               | cmp                 byte ptr [esi + 0x4b], dl
            //   7526                 | jne                 0x28
            //   8b4644               | mov                 eax, dword ptr [esi + 0x44]

        $sequence_6 = { eb04 8b44241c 8b542410 8b4e28 2bc2 3bc1 }
            // n = 6, score = 600
            //   eb04                 | jmp                 6
            //   8b44241c             | mov                 eax, dword ptr [esp + 0x1c]
            //   8b542410             | mov                 edx, dword ptr [esp + 0x10]
            //   8b4e28               | mov                 ecx, dword ptr [esi + 0x28]
            //   2bc2                 | sub                 eax, edx
            //   3bc1                 | cmp                 eax, ecx

        $sequence_7 = { 57 8d4c2414 895654 e8???????? 8d4c2410 c6465a01 c744242cffffffff }
            // n = 7, score = 600
            //   57                   | push                edi
            //   8d4c2414             | lea                 ecx, [esp + 0x14]
            //   895654               | mov                 dword ptr [esi + 0x54], edx
            //   e8????????           |                     
            //   8d4c2410             | lea                 ecx, [esp + 0x10]
            //   c6465a01             | mov                 byte ptr [esi + 0x5a], 1
            //   c744242cffffffff     | mov                 dword ptr [esp + 0x2c], 0xffffffff

        $sequence_8 = { 84c0 7406 09bd08010000 8b4c2454 8b542458 898d24010000 }
            // n = 6, score = 600
            //   84c0                 | test                al, al
            //   7406                 | je                  8
            //   09bd08010000         | or                  dword ptr [ebp + 0x108], edi
            //   8b4c2454             | mov                 ecx, dword ptr [esp + 0x54]
            //   8b542458             | mov                 edx, dword ptr [esp + 0x58]
            //   898d24010000         | mov                 dword ptr [ebp + 0x124], ecx

        $sequence_9 = { c744244817406700 894c244c 896c2450 89542454 e8???????? 8b5658 8b4008 }
            // n = 7, score = 600
            //   c744244817406700     | mov                 dword ptr [esp + 0x48], 0x674017
            //   894c244c             | mov                 dword ptr [esp + 0x4c], ecx
            //   896c2450             | mov                 dword ptr [esp + 0x50], ebp
            //   89542454             | mov                 dword ptr [esp + 0x54], edx
            //   e8????????           |                     
            //   8b5658               | mov                 edx, dword ptr [esi + 0x58]
            //   8b4008               | mov                 eax, dword ptr [eax + 8]

    condition:
        7 of them and filesize < 540672
}