rule win_bachosens_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.bachosens."
        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.bachosens"
        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 = { 4883ec08 4533c9 4c8bd9 458bc1 66443901 }
            // n = 5, score = 200
            //   4883ec08             | inc                 ebp
            //   4533c9               | lea                 eax, [ecx + 2]
            //   4c8bd9               | call                eax
            //   458bc1               | dec                 eax
            //   66443901             | mov                 ebp, eax

        $sequence_1 = { 33d2 0fb61f 4803f1 84db 740e 488bc7 }
            // n = 6, score = 200
            //   33d2                 | dec                 eax
            //   0fb61f               | mov                 dword ptr [eax], ecx
            //   4803f1               | dec                 eax
            //   84db                 | lea                 ecx, [0x2731f]
            //   740e                 | dec                 eax
            //   488bc7               | mov                 dword ptr [eax + 8], ebx

        $sequence_2 = { 4d2bda 49f7da 0f1f4000 66660f1f840000000000 430fb61403 410fb608 }
            // n = 6, score = 200
            //   4d2bda               | mov                 byte ptr [eax + edi], 0
            //   49f7da               | mov                 eax, 1
            //   0f1f4000             | dec                 eax
            //   66660f1f840000000000     | mov    ebp, dword ptr [esp + 0x18]
            //   430fb61403           | dec                 eax
            //   410fb608             | mov                 ebx, dword ptr [esp + 0x20]

        $sequence_3 = { 488bd1 488b4b50 e8???????? 85c0 7416 488b1b }
            // n = 6, score = 200
            //   488bd1               | xor                 edx, edx
            //   488b4b50             | inc                 ecx
            //   e8????????           |                     
            //   85c0                 | mov                 eax, 0x41c
            //   7416                 | dec                 eax
            //   488b1b               | mov                 ecx, eax

        $sequence_4 = { 6603c1 4803f9 0fb7c0 8b3482 33d2 }
            // n = 5, score = 200
            //   6603c1               | dec                 eax
            //   4803f9               | add                 edx, 0x31f
            //   0fb7c0               | dec                 eax
            //   8b3482               | mov                 ecx, edi
            //   33d2                 | dec                 eax

        $sequence_5 = { 4803f9 0fb7c0 8b3482 33d2 0fb61f 4803f1 84db }
            // n = 7, score = 200
            //   4803f9               | sar                 edx, 0x10
            //   0fb7c0               | dec                 eax
            //   8b3482               | mov                 esi, dword ptr [esp + 0x50]
            //   33d2                 | dec                 eax
            //   0fb61f               | mov                 edi, dword ptr [esp + 0x48]
            //   4803f1               | dec                 eax
            //   84db                 | mov                 ebx, dword ptr [esp + 0x78]

        $sequence_6 = { 8b442420 ffc0 89442420 4863442420 b933000000 }
            // n = 5, score = 200
            //   8b442420             | mov                 dword ptr [edi + 0x18], ebx
            //   ffc0                 | dec                 eax
            //   89442420             | test                eax, eax
            //   4863442420           | je                  0x1a1c
            //   b933000000           | dec                 eax

        $sequence_7 = { 4c2bda bbe0ff0000 90 450fb70413 0fb70a 418d409f 6683f819 }
            // n = 7, score = 200
            //   4c2bda               | mov                 ecx, ebx
            //   bbe0ff0000           | dec                 eax
            //   90                   | test                eax, eax
            //   450fb70413           | jne                 0x3fd
            //   0fb70a               | jne                 0x3b0
            //   418d409f             | dec                 eax
            //   6683f819             | mov                 ecx, ebp

        $sequence_8 = { ffc2 488d4001 803800 75f5 3bca 7557 }
            // n = 6, score = 200
            //   ffc2                 | dec                 eax
            //   488d4001             | mov                 eax, edi
            //   803800               | inc                 esp
            //   75f5                 | cmp                 byte ptr [ebx + 8], bh
            //   3bca                 | dec                 eax
            //   7557                 | test                eax, eax

        $sequence_9 = { 66390a 7417 488bc2 0f1f840000000000 ffc1 488d4002 66443908 }
            // n = 7, score = 200
            //   66390a               | mov                 byte ptr [esp + eax + 0xb0], 0x65
            //   7417                 | mov                 eax, dword ptr [esp + 0x20]
            //   488bc2               | mov                 eax, dword ptr [esp + 0x20]
            //   0f1f840000000000     | inc                 eax
            //   ffc1                 | mov                 dword ptr [esp + 0x20], eax
            //   488d4002             | dec                 eax
            //   66443908             | arpl                word ptr [esp + 0x20], ax

    condition:
        7 of them and filesize < 643072
}