rule win_microbackdoor_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.microbackdoor."
        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.microbackdoor"
        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 = { 56 ffd7 6810270000 ff15???????? }
            // n = 4, score = 100
            //   56                   | mov                 ebx, eax
            //   ffd7                 | dec                 eax
            //   6810270000           | lea                 eax, [ebp + 0x278]
            //   ff15????????         |                     

        $sequence_1 = { 8bce 0fb7811c100010 6689840dbcfbffff 03cb 6685c0 }
            // n = 5, score = 100
            //   8bce                 | mov                 dword ptr [esp + 0x28], eax
            //   0fb7811c100010       | inc                 ecx
            //   6689840dbcfbffff     | mov                 eax, dword ptr [ecx + 0x10]
            //   03cb                 | dec                 ebp
            //   6685c0               | mov                 ecx, dword ptr [ecx + 8]

        $sequence_2 = { 488b4c2448 4885c9 740e ff15???????? 488b9c2488000000 488b4c2478 4885c9 }
            // n = 7, score = 100
            //   488b4c2448           | dec                 eax
            //   4885c9               | mov                 ecx, dword ptr [esp + 0x48]
            //   740e                 | dec                 eax
            //   ff15????????         |                     
            //   488b9c2488000000     | test                ecx, ecx
            //   488b4c2478           | je                  0x10
            //   4885c9               | dec                 eax

        $sequence_3 = { 8d45fc 50 ff15???????? 8b3d???????? 8bf0 85f6 }
            // n = 6, score = 100
            //   8d45fc               | lea                 edx, [ebp - 0x20]
            //   50                   | mov                 dword ptr [ebp + 0x58], ebx
            //   ff15????????         |                     
            //   8b3d????????         |                     
            //   8bf0                 | dec                 eax
            //   85f6                 | mov                 ecx, dword ptr [esp + 0x50]

        $sequence_4 = { 5d c3 55 8bec ff750c ff15???????? 50 }
            // n = 7, score = 100
            //   5d                   | mov                 dword ptr [esp + 0x20], eax
            //   c3                   | dec                 eax
            //   55                   | mov                 ecx, dword ptr [esp + 0x38]
            //   8bec                 | dec                 esp
            //   ff750c               | lea                 eax, [ebp + 0x58]
            //   ff15????????         |                     
            //   50                   | dec                 eax

        $sequence_5 = { 33db 56 8b750c 43 85f6 0f84a9010000 }
            // n = 6, score = 100
            //   33db                 | mov                 ecx, esi
            //   56                   | movzx               eax, word ptr [ecx + 0x1000101c]
            //   8b750c               | mov                 word ptr [ebp + ecx - 0x444], ax
            //   43                   | add                 ecx, ebx
            //   85f6                 | test                ax, ax
            //   0f84a9010000         | pop                 ebp

        $sequence_6 = { 488b4c2450 8bd8 488d8578020000 4533c9 4533c0 }
            // n = 5, score = 100
            //   488b4c2450           | add                 esp, 0x2d0
            //   8bd8                 | pop                 edi
            //   488d8578020000       | ret                 
            //   4533c9               | dec                 eax
            //   4533c0               | lea                 ecx, [0x67ae]

        $sequence_7 = { ff750c 57 ff15???????? 57 ff7508 e8???????? }
            // n = 6, score = 100
            //   ff750c               | dec                 eax
            //   57                   | lea                 eax, [esp + 0x44]
            //   ff15????????         |                     
            //   57                   | xor                 ecx, ecx
            //   ff7508               | dec                 eax
            //   e8????????           |                     

        $sequence_8 = { 4889442430 488d442444 33c9 4889442428 418b4110 4d8b4908 89442420 }
            // n = 7, score = 100
            //   4889442430           | inc                 ebp
            //   488d442444           | test                edi, edi
            //   33c9                 | dec                 eax
            //   4889442428           | mov                 ecx, ebx
            //   418b4110             | jmp                 0x19
            //   4d8b4908             | dec                 eax
            //   89442420             | lea                 ecx, [0x32f6]

        $sequence_9 = { 833f0a 7207 33c0 e9???????? 53 33db 56 }
            // n = 7, score = 100
            //   833f0a               | mov                 eax, ebx
            //   7207                 | jmp                 0x3a
            //   33c0                 | push                dword ptr [ebp + 0xc]
            //   e9????????           |                     
            //   53                   | push                edi
            //   33db                 | push                edi
            //   56                   | push                dword ptr [ebp + 8]

        $sequence_10 = { 8bec 83ec18 56 57 33c0 c745fc14000000 8d7de8 }
            // n = 7, score = 100
            //   8bec                 | inc                 ebp
            //   83ec18               | xor                 ecx, ecx
            //   56                   | inc                 ebp
            //   57                   | xor                 eax, eax
            //   33c0                 | dec                 eax
            //   c745fc14000000       | lea                 ecx, [0x44f2]
            //   8d7de8               | dec                 eax

        $sequence_11 = { 488bcb ff15???????? eb14 ff15???????? 488d0df6320000 8bd0 }
            // n = 6, score = 100
            //   488bcb               | dec                 eax
            //   ff15????????         |                     
            //   eb14                 | arpl                di, cx
            //   ff15????????         |                     
            //   488d0df6320000       | dec                 eax
            //   8bd0                 | lea                 edx, [0x733a]

        $sequence_12 = { 488b4c2438 4c8d4558 488d55e0 895d58 }
            // n = 4, score = 100
            //   488b4c2438           | mov                 edx, eax
            //   4c8d4558             | dec                 eax
            //   488d55e0             | mov                 ebx, dword ptr [esp + 0x2f8]
            //   895d58               | dec                 eax

        $sequence_13 = { e8???????? 448bf8 488bcf ff15???????? 4585ff }
            // n = 5, score = 100
            //   e8????????           |                     
            //   448bf8               | nop                 dword ptr [eax + eax]
            //   488bcf               | inc                 esp
            //   ff15????????         |                     
            //   4585ff               | movzx               eax, byte ptr [esi]

        $sequence_14 = { 488b9c24f8020000 4881c4d0020000 5f c3 ff15???????? 488d0dae670000 8bd0 }
            // n = 7, score = 100
            //   488b9c24f8020000     | dec                 ecx
            //   4881c4d0020000       | add                 ecx, esi
            //   5f                   | inc                 esp
            //   c3                   | mov                 edi, eax
            //   ff15????????         |                     
            //   488d0dae670000       | dec                 eax
            //   8bd0                 | mov                 ecx, edi

        $sequence_15 = { 0f1f840000000000 440fb606 4863cf 488d153a730000 4903ce ff15???????? }
            // n = 6, score = 100
            //   0f1f840000000000     | mov                 ebx, dword ptr [esp + 0x88]
            //   440fb606             | dec                 eax
            //   4863cf               | mov                 ecx, dword ptr [esp + 0x78]
            //   488d153a730000       | dec                 eax
            //   4903ce               | test                ecx, ecx
            //   ff15????????         |                     

    condition:
        7 of them and filesize < 123904
}