rule win_crutch_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.crutch."
        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.crutch"
        malpedia_rule_date = "20260916"
        malpedia_hash = "53a643781c18e08f4a50949af60172d837a0b6f6"
        malpedia_version = "20260917"
        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 = { 8d45a8 50 e8???????? 57 e8???????? 59 ff75b0 }
            // n = 7, score = 100
            //   8d45a8               | lea                 eax, [ebp - 0x58]
            //   50                   | push                eax
            //   e8????????           |                     
            //   57                   | push                edi
            //   e8????????           |                     
            //   59                   | pop                 ecx
            //   ff75b0               | push                dword ptr [ebp - 0x50]

        $sequence_1 = { 8b908c030000 8911 33c0 c3 8b80b04a0000 8901 33c0 }
            // n = 7, score = 100
            //   8b908c030000         | mov                 edx, dword ptr [eax + 0x38c]
            //   8911                 | mov                 dword ptr [ecx], edx
            //   33c0                 | xor                 eax, eax
            //   c3                   | ret                 
            //   8b80b04a0000         | mov                 eax, dword ptr [eax + 0x4ab0]
            //   8901                 | mov                 dword ptr [ecx], eax
            //   33c0                 | xor                 eax, eax

        $sequence_2 = { 0fb680805b0110 ff24855c5b0110 b8???????? eb36 b8???????? eb2f b8???????? }
            // n = 7, score = 100
            //   0fb680805b0110       | movzx               eax, byte ptr [eax + 0x10015b80]
            //   ff24855c5b0110       | jmp                 dword ptr [eax*4 + 0x10015b5c]
            //   b8????????           |                     
            //   eb36                 | jmp                 0x38
            //   b8????????           |                     
            //   eb2f                 | jmp                 0x31
            //   b8????????           |                     

        $sequence_3 = { 8b8394070000 8b4918 8d542410 52 }
            // n = 4, score = 100
            //   8b8394070000         | mov                 eax, dword ptr [ebx + 0x794]
            //   8b4918               | mov                 ecx, dword ptr [ecx + 0x18]
            //   8d542410             | lea                 edx, [esp + 0x10]
            //   52                   | push                edx

        $sequence_4 = { 8b8528e5ffff 8b0c8588980710 8b8524e5ffff f644080480 0f8475030000 8b9530e5ffff 33ff }
            // n = 7, score = 100
            //   8b8528e5ffff         | mov                 eax, dword ptr [ebp - 0x1ad8]
            //   8b0c8588980710       | mov                 ecx, dword ptr [eax*4 + 0x10079888]
            //   8b8524e5ffff         | mov                 eax, dword ptr [ebp - 0x1adc]
            //   f644080480           | test                byte ptr [eax + ecx + 4], 0x80
            //   0f8475030000         | je                  0x37b
            //   8b9530e5ffff         | mov                 edx, dword ptr [ebp - 0x1ad0]
            //   33ff                 | xor                 edi, edi

        $sequence_5 = { 52 8d542440 52 8b5038 8b00 51 53 }
            // n = 7, score = 100
            //   52                   | push                edx
            //   8d542440             | lea                 edx, [esp + 0x40]
            //   52                   | push                edx
            //   8b5038               | mov                 edx, dword ptr [eax + 0x38]
            //   8b00                 | mov                 eax, dword ptr [eax]
            //   51                   | push                ecx
            //   53                   | push                ebx

        $sequence_6 = { 8b8fe8030000 51 ffd0 83c410 3bc3 0f8477010000 }
            // n = 6, score = 100
            //   8b8fe8030000         | mov                 ecx, dword ptr [edi + 0x3e8]
            //   51                   | push                ecx
            //   ffd0                 | call                eax
            //   83c410               | add                 esp, 0x10
            //   3bc3                 | cmp                 eax, ebx
            //   0f8477010000         | je                  0x17d

        $sequence_7 = { 8be5 5d c20400 6a74 b8???????? }
            // n = 5, score = 100
            //   8be5                 | mov                 esp, ebp
            //   5d                   | pop                 ebp
            //   c20400               | ret                 4
            //   6a74                 | push                0x74
            //   b8????????           |                     

        $sequence_8 = { 8b542420 33c0 3919 5f 0f95c0 5e 8982e0030000 }
            // n = 7, score = 100
            //   8b542420             | mov                 edx, dword ptr [esp + 0x20]
            //   33c0                 | xor                 eax, eax
            //   3919                 | cmp                 dword ptr [ecx], ebx
            //   5f                   | pop                 edi
            //   0f95c0               | setne               al
            //   5e                   | pop                 esi
            //   8982e0030000         | mov                 dword ptr [edx + 0x3e0], eax

        $sequence_9 = { 8bc3 899df4feffff 888405fcfeffff 40 3d00010000 7cf1 899df0feffff }
            // n = 7, score = 100
            //   8bc3                 | mov                 eax, ebx
            //   899df4feffff         | mov                 dword ptr [ebp - 0x10c], ebx
            //   888405fcfeffff       | mov                 byte ptr [ebp + eax - 0x104], al
            //   40                   | inc                 eax
            //   3d00010000           | cmp                 eax, 0x100
            //   7cf1                 | jl                  0xfffffff3
            //   899df0feffff         | mov                 dword ptr [ebp - 0x110], ebx

    condition:
        7 of them and filesize < 1067008
}