rule win_byeby_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.byeby."
        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.byeby"
        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 = { 03f8 3bfb 7419 6a00 8bc3 }
            // n = 5, score = 100
            //   03f8                 | add                 edi, eax
            //   3bfb                 | cmp                 edi, ebx
            //   7419                 | je                  0x1b
            //   6a00                 | push                0
            //   8bc3                 | mov                 eax, ebx

        $sequence_1 = { 8944240c 3b01 0f82ecfeffff eb1e 8d8424bc030000 50 68???????? }
            // n = 7, score = 100
            //   8944240c             | mov                 dword ptr [esp + 0xc], eax
            //   3b01                 | cmp                 eax, dword ptr [ecx]
            //   0f82ecfeffff         | jb                  0xfffffef2
            //   eb1e                 | jmp                 0x20
            //   8d8424bc030000       | lea                 eax, [esp + 0x3bc]
            //   50                   | push                eax
            //   68????????           |                     

        $sequence_2 = { 68ffff0000 53 ff15???????? 53 8d4c2430 e8???????? }
            // n = 6, score = 100
            //   68ffff0000           | push                0xffff
            //   53                   | push                ebx
            //   ff15????????         |                     
            //   53                   | push                ebx
            //   8d4c2430             | lea                 ecx, [esp + 0x30]
            //   e8????????           |                     

        $sequence_3 = { c1ff05 83e61f c1e606 8b0cbd18ab0110 f6440e0401 743d 833c0eff }
            // n = 7, score = 100
            //   c1ff05               | sar                 edi, 5
            //   83e61f               | and                 esi, 0x1f
            //   c1e606               | shl                 esi, 6
            //   8b0cbd18ab0110       | mov                 ecx, dword ptr [edi*4 + 0x1001ab18]
            //   f6440e0401           | test                byte ptr [esi + ecx + 4], 1
            //   743d                 | je                  0x3f
            //   833c0eff             | cmp                 dword ptr [esi + ecx], -1

        $sequence_4 = { 8d942438030000 c744241400000000 8d4c2414 c78424380300006578706c c784243c0300006f726572 }
            // n = 5, score = 100
            //   8d942438030000       | lea                 edx, [esp + 0x338]
            //   c744241400000000     | mov                 dword ptr [esp + 0x14], 0
            //   8d4c2414             | lea                 ecx, [esp + 0x14]
            //   c78424380300006578706c     | mov    dword ptr [esp + 0x338], 0x6c707865
            //   c784243c0300006f726572     | mov    dword ptr [esp + 0x33c], 0x7265726f

        $sequence_5 = { ffd6 8b3d???????? 68c0d40100 ffd7 8b35???????? 68???????? ffd6 }
            // n = 7, score = 100
            //   ffd6                 | call                esi
            //   8b3d????????         |                     
            //   68c0d40100           | push                0x1d4c0
            //   ffd7                 | call                edi
            //   8b35????????         |                     
            //   68????????           |                     
            //   ffd6                 | call                esi

        $sequence_6 = { c705????????00000000 ffd6 c705????????00000000 e9???????? 8b35???????? 8d84243c060000 68???????? }
            // n = 7, score = 100
            //   c705????????00000000     |     
            //   ffd6                 | call                esi
            //   c705????????00000000     |     
            //   e9????????           |                     
            //   8b35????????         |                     
            //   8d84243c060000       | lea                 eax, [esp + 0x63c]
            //   68????????           |                     

        $sequence_7 = { c785acfeffff01010000 50 6a00 6a00 6a00 6a01 }
            // n = 6, score = 100
            //   c785acfeffff01010000     | mov    dword ptr [ebp - 0x154], 0x101
            //   50                   | push                eax
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   6a01                 | push                1

        $sequence_8 = { 8d45d0 c745e06b65726e 50 8d45e0 c745e4656c3332 50 }
            // n = 6, score = 100
            //   8d45d0               | lea                 eax, [ebp - 0x30]
            //   c745e06b65726e       | mov                 dword ptr [ebp - 0x20], 0x6e72656b
            //   50                   | push                eax
            //   8d45e0               | lea                 eax, [ebp - 0x20]
            //   c745e4656c3332       | mov                 dword ptr [ebp - 0x1c], 0x32336c65
            //   50                   | push                eax

        $sequence_9 = { e8???????? 83c40c 817d8421030900 7510 8bcb e8???????? }
            // n = 6, score = 100
            //   e8????????           |                     
            //   83c40c               | add                 esp, 0xc
            //   817d8421030900       | cmp                 dword ptr [ebp - 0x7c], 0x90321
            //   7510                 | jne                 0x12
            //   8bcb                 | mov                 ecx, ebx
            //   e8????????           |                     

    condition:
        7 of them and filesize < 253952
}