rule win_wannacryptor_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        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 = "20230124"
        malpedia_hash = "2ee0eebba83dce3d019a90519f2f972c0fcf9686"
        malpedia_version = "20230125"
        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 = { 8b74243c 8bca c1e917 c1e81e }
            // n = 4, score = 600
            //   8b74243c             | mov                 esi, dword ptr [esp + 0x3c]
            //   8bca                 | mov                 ecx, edx
            //   c1e917               | shr                 ecx, 0x17
            //   c1e81e               | shr                 eax, 0x1e

        $sequence_1 = { 8bf0 8975dc 83feff 750a 50 }
            // n = 5, score = 600
            //   8bf0                 | mov                 esi, eax
            //   8975dc               | mov                 dword ptr [ebp - 0x24], esi
            //   83feff               | cmp                 esi, -1
            //   750a                 | jne                 0xc
            //   50                   | push                eax

        $sequence_2 = { a1???????? 8b0d???????? 8944240c 8d44240c }
            // n = 4, score = 600
            //   a1????????           |                     
            //   8b0d????????         |                     
            //   8944240c             | mov                 dword ptr [esp + 0xc], eax
            //   8d44240c             | lea                 eax, [esp + 0xc]

        $sequence_3 = { 5b 59 c20c00 8bce e8???????? 84c0 }
            // n = 6, score = 600
            //   5b                   | pop                 ebx
            //   59                   | pop                 ecx
            //   c20c00               | ret                 0xc
            //   8bce                 | mov                 ecx, esi
            //   e8????????           |                     
            //   84c0                 | test                al, al

        $sequence_4 = { 895c242c ff15???????? 85c0 7e7e 8d4c243c 51 }
            // n = 6, score = 600
            //   895c242c             | mov                 dword ptr [esp + 0x2c], ebx
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   7e7e                 | jle                 0x80
            //   8d4c243c             | lea                 ecx, [esp + 0x3c]
            //   51                   | push                ecx

        $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 = { 0f8c8a000000 8b4d04 8b5500 8d442414 6a04 50 }
            // n = 6, score = 600
            //   0f8c8a000000         | jl                  0x90
            //   8b4d04               | mov                 ecx, dword ptr [ebp + 4]
            //   8b5500               | mov                 edx, dword ptr [ebp]
            //   8d442414             | lea                 eax, [esp + 0x14]
            //   6a04                 | push                4
            //   50                   | push                eax

        $sequence_7 = { 83ec10 56 8bf1 57 8b7c241c 8b4670 85c0 }
            // n = 7, score = 600
            //   83ec10               | sub                 esp, 0x10
            //   56                   | push                esi
            //   8bf1                 | mov                 esi, ecx
            //   57                   | push                edi
            //   8b7c241c             | mov                 edi, dword ptr [esp + 0x1c]
            //   8b4670               | mov                 eax, dword ptr [esi + 0x70]
            //   85c0                 | test                eax, eax

        $sequence_8 = { 8b4678 8d7e44 85c0 755f 8b17 }
            // n = 5, score = 600
            //   8b4678               | mov                 eax, dword ptr [esi + 0x78]
            //   8d7e44               | lea                 edi, [esi + 0x44]
            //   85c0                 | test                eax, eax
            //   755f                 | jne                 0x61
            //   8b17                 | mov                 edx, dword ptr [edi]

        $sequence_9 = { 7406 09bd08010000 8b4c2454 8b542458 898d24010000 8b4c244c }
            // n = 6, score = 600
            //   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
            //   8b4c244c             | mov                 ecx, dword ptr [esp + 0x4c]

    condition:
        7 of them and filesize < 540672
}