rule win_wannacryptor_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-07-11"
        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 = "20230705"
        malpedia_hash = "42d0574f4405bd7d2b154d321d345acb18834a41"
        malpedia_version = "20230715"
        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 = { c744244817406700 894c244c 896c2450 89542454 }
            // n = 4, 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

        $sequence_1 = { 55 8be9 8b8c2444020000 56 57 51 c744241401000000 }
            // n = 7, score = 600
            //   55                   | push                ebp
            //   8be9                 | mov                 ebp, ecx
            //   8b8c2444020000       | mov                 ecx, dword ptr [esp + 0x244]
            //   56                   | push                esi
            //   57                   | push                edi
            //   51                   | push                ecx
            //   c744241401000000     | mov                 dword ptr [esp + 0x14], 1

        $sequence_2 = { 8bf0 8975dc 83feff 750a 50 8d55f0 52 }
            // n = 7, score = 600
            //   8bf0                 | mov                 esi, eax
            //   8975dc               | mov                 dword ptr [ebp - 0x24], esi
            //   83feff               | cmp                 esi, -1
            //   750a                 | jne                 0xc
            //   50                   | push                eax
            //   8d55f0               | lea                 edx, [ebp - 0x10]
            //   52                   | push                edx

        $sequence_3 = { 56 51 57 ffd5 85c0 7418 8a442413 }
            // n = 7, score = 600
            //   56                   | push                esi
            //   51                   | push                ecx
            //   57                   | push                edi
            //   ffd5                 | call                ebp
            //   85c0                 | test                eax, eax
            //   7418                 | je                  0x1a
            //   8a442413             | mov                 al, byte ptr [esp + 0x13]

        $sequence_4 = { 8bce e8???????? 85db 7403 8b5b04 }
            // n = 5, score = 600
            //   8bce                 | mov                 ecx, esi
            //   e8????????           |                     
            //   85db                 | test                ebx, ebx
            //   7403                 | je                  5
            //   8b5b04               | mov                 ebx, dword ptr [ebx + 4]

        $sequence_5 = { ff15???????? 50 e8???????? 85c0 742e 8b4004 8d542404 }
            // n = 7, score = 600
            //   ff15????????         |                     
            //   50                   | push                eax
            //   e8????????           |                     
            //   85c0                 | test                eax, eax
            //   742e                 | je                  0x30
            //   8b4004               | mov                 eax, dword ptr [eax + 4]
            //   8d542404             | lea                 edx, [esp + 4]

        $sequence_6 = { f7f9 85c0 7443 3bf9 7c3f }
            // n = 5, score = 600
            //   f7f9                 | idiv                ecx
            //   85c0                 | test                eax, eax
            //   7443                 | je                  0x45
            //   3bf9                 | cmp                 edi, ecx
            //   7c3f                 | jl                  0x41

        $sequence_7 = { 51 8954243c ff15???????? 8b442428 8b4c242c }
            // n = 5, score = 600
            //   51                   | push                ecx
            //   8954243c             | mov                 dword ptr [esp + 0x3c], edx
            //   ff15????????         |                     
            //   8b442428             | mov                 eax, dword ptr [esp + 0x28]
            //   8b4c242c             | mov                 ecx, dword ptr [esp + 0x2c]

        $sequence_8 = { 57 837d0000 0f85d2000000 837d04ff 0f85c8000000 53 8d9d40010000 }
            // n = 7, score = 600
            //   57                   | push                edi
            //   837d0000             | cmp                 dword ptr [ebp], 0
            //   0f85d2000000         | jne                 0xd8
            //   837d04ff             | cmp                 dword ptr [ebp + 4], -1
            //   0f85c8000000         | jne                 0xce
            //   53                   | push                ebx
            //   8d9d40010000         | lea                 ebx, [ebp + 0x140]

        $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
}