rule win_void_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.void."
        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.void"
        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 = { 7426 66660f1f840000000000 c70000000000 c7400400000000 c7400800000000 83c00c 83e901 }
            // n = 7, score = 200
            //   7426                 | je                  0x28
            //   66660f1f840000000000     | nop    word ptr [eax + eax]
            //   c70000000000         | mov                 dword ptr [eax], 0
            //   c7400400000000       | mov                 dword ptr [eax + 4], 0
            //   c7400800000000       | mov                 dword ptr [eax + 8], 0
            //   83c00c               | add                 eax, 0xc
            //   83e901               | sub                 ecx, 1

        $sequence_1 = { 84c0 752e 6a02 8d4d30 e8???????? 8d4530 c745fc02000000 }
            // n = 7, score = 200
            //   84c0                 | test                al, al
            //   752e                 | jne                 0x30
            //   6a02                 | push                2
            //   8d4d30               | lea                 ecx, [ebp + 0x30]
            //   e8????????           |                     
            //   8d4530               | lea                 eax, [ebp + 0x30]
            //   c745fc02000000       | mov                 dword ptr [ebp - 4], 2

        $sequence_2 = { 83c801 85c0 7537 ff742428 68???????? 56 e8???????? }
            // n = 7, score = 200
            //   83c801               | or                  eax, 1
            //   85c0                 | test                eax, eax
            //   7537                 | jne                 0x39
            //   ff742428             | push                dword ptr [esp + 0x28]
            //   68????????           |                     
            //   56                   | push                esi
            //   e8????????           |                     

        $sequence_3 = { 6a03 e8???????? 8d45b8 c745fc03000000 50 8bcb c745ec01000000 }
            // n = 7, score = 200
            //   6a03                 | push                3
            //   e8????????           |                     
            //   8d45b8               | lea                 eax, [ebp - 0x48]
            //   c745fc03000000       | mov                 dword ptr [ebp - 4], 3
            //   50                   | push                eax
            //   8bcb                 | mov                 ecx, ebx
            //   c745ec01000000       | mov                 dword ptr [ebp - 0x14], 1

        $sequence_4 = { 8b4008 8b34b0 85f6 757d 8b45e4 85c0 7404 }
            // n = 7, score = 200
            //   8b4008               | mov                 eax, dword ptr [eax + 8]
            //   8b34b0               | mov                 esi, dword ptr [eax + esi*4]
            //   85f6                 | test                esi, esi
            //   757d                 | jne                 0x7f
            //   8b45e4               | mov                 eax, dword ptr [ebp - 0x1c]
            //   85c0                 | test                eax, eax
            //   7404                 | je                  6

        $sequence_5 = { 57 56 e8???????? 8b4da0 83c40c 8b45bc 8801 }
            // n = 7, score = 200
            //   57                   | push                edi
            //   56                   | push                esi
            //   e8????????           |                     
            //   8b4da0               | mov                 ecx, dword ptr [ebp - 0x60]
            //   83c40c               | add                 esp, 0xc
            //   8b45bc               | mov                 eax, dword ptr [ebp - 0x44]
            //   8801                 | mov                 byte ptr [ecx], al

        $sequence_6 = { 8937 dd9dc0fcffff 85c0 7425 f20f1005???????? 660f6ec8 f30fe6c9 }
            // n = 7, score = 200
            //   8937                 | mov                 dword ptr [edi], esi
            //   dd9dc0fcffff         | fstp                qword ptr [ebp - 0x340]
            //   85c0                 | test                eax, eax
            //   7425                 | je                  0x27
            //   f20f1005????????     |                     
            //   660f6ec8             | movd                xmm1, eax
            //   f30fe6c9             | cvtdq2pd            xmm1, xmm1

        $sequence_7 = { 8b5504 85c9 8b7c241c 8bca 8b5c2418 57 8b02 }
            // n = 7, score = 200
            //   8b5504               | mov                 edx, dword ptr [ebp + 4]
            //   85c9                 | test                ecx, ecx
            //   8b7c241c             | mov                 edi, dword ptr [esp + 0x1c]
            //   8bca                 | mov                 ecx, edx
            //   8b5c2418             | mov                 ebx, dword ptr [esp + 0x18]
            //   57                   | push                edi
            //   8b02                 | mov                 eax, dword ptr [edx]

    condition:
        7 of them and filesize < 2744320
}