rule win_wannacryptor_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-08-05"
        version = "1"
        description = "Detects win.wannacryptor."
        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.wannacryptor"
        malpedia_rule_date = "20220805"
        malpedia_hash = "6ec06c64bcfdbeda64eff021c766b4ce34542b71"
        malpedia_version = "20220808"
        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 = { 8bd1 c1fa08 8810 40 8808 40 }
            // n = 6, score = 600
            //   8bd1                 | mov                 edx, ecx
            //   c1fa08               | sar                 edx, 8
            //   8810                 | mov                 byte ptr [eax], dl
            //   40                   | inc                 eax
            //   8808                 | mov                 byte ptr [eax], cl
            //   40                   | inc                 eax

        $sequence_2 = { 8b16 8b4604 894204 8b4e0c 3bcb }
            // n = 5, score = 600
            //   8b16                 | mov                 edx, dword ptr [esi]
            //   8b4604               | mov                 eax, dword ptr [esi + 4]
            //   894204               | mov                 dword ptr [edx + 4], eax
            //   8b4e0c               | mov                 ecx, dword ptr [esi + 0xc]
            //   3bcb                 | cmp                 ecx, ebx

        $sequence_3 = { 8b4604 894204 8b4e0c 3bcb 741e }
            // n = 5, score = 600
            //   8b4604               | mov                 eax, dword ptr [esi + 4]
            //   894204               | mov                 dword ptr [edx + 4], eax
            //   8b4e0c               | mov                 ecx, dword ptr [esi + 0xc]
            //   3bcb                 | cmp                 ecx, ebx
            //   741e                 | je                  0x20

        $sequence_4 = { 8b442418 8bc8 40 83f964 89442418 7e10 }
            // n = 6, score = 600
            //   8b442418             | mov                 eax, dword ptr [esp + 0x18]
            //   8bc8                 | mov                 ecx, eax
            //   40                   | inc                 eax
            //   83f964               | cmp                 ecx, 0x64
            //   89442418             | mov                 dword ptr [esp + 0x18], eax
            //   7e10                 | jle                 0x12

        $sequence_5 = { eb03 8b4b04 6a01 51 8b4820 6a30 51 }
            // n = 7, score = 600
            //   eb03                 | jmp                 5
            //   8b4b04               | mov                 ecx, dword ptr [ebx + 4]
            //   6a01                 | push                1
            //   51                   | push                ecx
            //   8b4820               | mov                 ecx, dword ptr [eax + 0x20]
            //   6a30                 | push                0x30
            //   51                   | push                ecx

        $sequence_6 = { 53 8b5c2468 53 50 8b842494000000 51 }
            // n = 6, score = 600
            //   53                   | push                ebx
            //   8b5c2468             | mov                 ebx, dword ptr [esp + 0x68]
            //   53                   | push                ebx
            //   50                   | push                eax
            //   8b842494000000       | mov                 eax, dword ptr [esp + 0x94]
            //   51                   | push                ecx

        $sequence_7 = { 8d542410 6a04 52 6805100000 68ffff0000 }
            // n = 5, score = 600
            //   8d542410             | lea                 edx, [esp + 0x10]
            //   6a04                 | push                4
            //   52                   | push                edx
            //   6805100000           | push                0x1005
            //   68ffff0000           | push                0xffff

        $sequence_8 = { 8b48f8 8b4674 3bc8 7d16 2bc1 }
            // n = 5, score = 600
            //   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_9 = { 8b442424 50 ff15???????? 8b4c2408 8b54240c }
            // n = 5, score = 600
            //   8b442424             | mov                 eax, dword ptr [esp + 0x24]
            //   50                   | push                eax
            //   ff15????????         |                     
            //   8b4c2408             | mov                 ecx, dword ptr [esp + 8]
            //   8b54240c             | mov                 edx, dword ptr [esp + 0xc]

    condition:
        7 of them and filesize < 540672
}