rule win_compfun_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.compfun."
        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.compfun"
        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 = { 50 a1???????? 56 ff506c }
            // n = 4, score = 300
            //   50                   | push                eax
            //   a1????????           |                     
            //   56                   | push                esi
            //   ff506c               | call                dword ptr [eax + 0x6c]

        $sequence_1 = { 40 8d0443 50 a1???????? }
            // n = 4, score = 300
            //   40                   | inc                 eax
            //   8d0443               | lea                 eax, [ebx + eax*2]
            //   50                   | push                eax
            //   a1????????           |                     

        $sequence_2 = { 6a2a 5a 6a2e 59 }
            // n = 4, score = 300
            //   6a2a                 | push                0x2a
            //   5a                   | pop                 edx
            //   6a2e                 | push                0x2e
            //   59                   | pop                 ecx

        $sequence_3 = { 50 57 ffd3 89461c 85c0 }
            // n = 5, score = 300
            //   50                   | push                eax
            //   57                   | push                edi
            //   ffd3                 | call                ebx
            //   89461c               | mov                 dword ptr [esi + 0x1c], eax
            //   85c0                 | test                eax, eax

        $sequence_4 = { 6a2e 59 668945e8 33c0 }
            // n = 4, score = 300
            //   6a2e                 | push                0x2e
            //   59                   | pop                 ecx
            //   668945e8             | mov                 word ptr [ebp - 0x18], ax
            //   33c0                 | xor                 eax, eax

        $sequence_5 = { 33c0 68fc7f0000 50 6689857c7affff }
            // n = 4, score = 300
            //   33c0                 | xor                 eax, eax
            //   68fc7f0000           | push                0x7ffc
            //   50                   | push                eax
            //   6689857c7affff       | mov                 word ptr [ebp - 0x8584], ax

        $sequence_6 = { 56 e8???????? 83c40c c746084b657920 }
            // n = 4, score = 300
            //   56                   | push                esi
            //   e8????????           |                     
            //   83c40c               | add                 esp, 0xc
            //   c746084b657920       | mov                 dword ptr [esi + 8], 0x2079654b

        $sequence_7 = { 68???????? 8d85d8fdffff 50 a1???????? }
            // n = 4, score = 300
            //   68????????           |                     
            //   8d85d8fdffff         | lea                 eax, [ebp - 0x228]
            //   50                   | push                eax
            //   a1????????           |                     

        $sequence_8 = { 034c2460 488b442450 894820 488b4c2450 }
            // n = 4, score = 100
            //   034c2460             | lea                 edx, [esp + 0x40]
            //   488b442450           | dec                 eax
            //   894820               | mov                 ecx, dword ptr [esp + 0x70]
            //   488b4c2450           | add                 ecx, dword ptr [esp + 0x2c]

        $sequence_9 = { 03c1 89442420 8b542438 486bd218 }
            // n = 4, score = 100
            //   03c1                 | movzx               eax, byte ptr [eax + eax]
            //   89442420             | mov                 byte ptr [ecx + edx], al
            //   8b542438             | mov                 eax, dword ptr [esp + 0x18]
            //   486bd218             | add                 eax, ecx

        $sequence_10 = { 034c242c 488b442470 894820 488d542440 }
            // n = 4, score = 100
            //   034c242c             | add                 eax, dword ptr [esp + 0x2c]
            //   488b442470           | mov                 ecx, eax
            //   894820               | dec                 eax
            //   488d542440           | mov                 dword ptr [esp + 0x48], eax

        $sequence_11 = { 0344242c 8bc8 e8???????? 4889442448 }
            // n = 4, score = 100
            //   0344242c             | add                 eax, dword ptr [esp + 0x2c]
            //   8bc8                 | mov                 ecx, eax
            //   e8????????           |                     
            //   4889442448           | dec                 eax

        $sequence_12 = { 03c1 89442420 8b4c2438 488b442450 }
            // n = 4, score = 100
            //   03c1                 | dec                 eax
            //   89442420             | mov                 eax, dword ptr [esp + 0x38]
            //   8b4c2438             | inc                 edx
            //   488b442450           | movzx               eax, byte ptr [eax + eax]

        $sequence_13 = { 03c1 4863d0 488b4c2430 488b442438 }
            // n = 4, score = 100
            //   03c1                 | add                 ecx, dword ptr [esp + 0x60]
            //   4863d0               | dec                 eax
            //   488b4c2430           | mov                 eax, dword ptr [esp + 0x50]
            //   488b442438           | mov                 dword ptr [eax + 0x20], ecx

        $sequence_14 = { 03c1 89442420 8b442420 83c001 }
            // n = 4, score = 100
            //   03c1                 | add                 ecx, dword ptr [esp + 0x60]
            //   89442420             | dec                 eax
            //   8b442420             | mov                 eax, dword ptr [esp + 0x50]
            //   83c001               | mov                 dword ptr [eax + 0x20], ecx

        $sequence_15 = { 03c1 89442434 8b442430 39442434 }
            // n = 4, score = 100
            //   03c1                 | mov                 dword ptr [esp + 0x20], eax
            //   89442434             | mov                 eax, dword ptr [esp + 0x20]
            //   8b442430             | add                 eax, 0xa
            //   39442434             | add                 eax, ecx

    condition:
        7 of them and filesize < 402432
}