rule win_orpcbackdoor_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.orpcbackdoor."
        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.orpcbackdoor"
        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 = { 8a45ff 8bca c1f906 83e23f 6bd238 8b0c8d20cc0610 }
            // n = 6, score = 100
            //   8a45ff               | mov                 al, byte ptr [ebp - 1]
            //   8bca                 | mov                 ecx, edx
            //   c1f906               | sar                 ecx, 6
            //   83e23f               | and                 edx, 0x3f
            //   6bd238               | imul                edx, edx, 0x38
            //   8b0c8d20cc0610       | mov                 ecx, dword ptr [ecx*4 + 0x1006cc20]

        $sequence_1 = { 8d8d70fcfeff e8???????? 8d8d00fafeff e8???????? 8d8d68fafeff e8???????? }
            // n = 6, score = 100
            //   8d8d70fcfeff         | lea                 ecx, [ebp - 0x10390]
            //   e8????????           |                     
            //   8d8d00fafeff         | lea                 ecx, [ebp - 0x10600]
            //   e8????????           |                     
            //   8d8d68fafeff         | lea                 ecx, [ebp - 0x10598]
            //   e8????????           |                     

        $sequence_2 = { 8b45f0 ff704c e8???????? 59 59 }
            // n = 5, score = 100
            //   8b45f0               | mov                 eax, dword ptr [ebp - 0x10]
            //   ff704c               | push                dword ptr [eax + 0x4c]
            //   e8????????           |                     
            //   59                   | pop                 ecx
            //   59                   | pop                 ecx

        $sequence_3 = { ff7054 8b45fc ff7050 8b45fc ff7050 8b4dfc e8???????? }
            // n = 7, score = 100
            //   ff7054               | push                dword ptr [eax + 0x54]
            //   8b45fc               | mov                 eax, dword ptr [ebp - 4]
            //   ff7050               | push                dword ptr [eax + 0x50]
            //   8b45fc               | mov                 eax, dword ptr [ebp - 4]
            //   ff7050               | push                dword ptr [eax + 0x50]
            //   8b4dfc               | mov                 ecx, dword ptr [ebp - 4]
            //   e8????????           |                     

        $sequence_4 = { 0fbe00 8b4d10 0fbe09 3bc1 7507 8b45f8 40 }
            // n = 7, score = 100
            //   0fbe00               | movsx               eax, byte ptr [eax]
            //   8b4d10               | mov                 ecx, dword ptr [ebp + 0x10]
            //   0fbe09               | movsx               ecx, byte ptr [ecx]
            //   3bc1                 | cmp                 eax, ecx
            //   7507                 | jne                 9
            //   8b45f8               | mov                 eax, dword ptr [ebp - 8]
            //   40                   | inc                 eax

        $sequence_5 = { 8d8d0cfcfeff e8???????? 68???????? 8d8dc4fbfeff e8???????? 8d8de8f6feff e8???????? }
            // n = 7, score = 100
            //   8d8d0cfcfeff         | lea                 ecx, [ebp - 0x103f4]
            //   e8????????           |                     
            //   68????????           |                     
            //   8d8dc4fbfeff         | lea                 ecx, [ebp - 0x1043c]
            //   e8????????           |                     
            //   8d8de8f6feff         | lea                 ecx, [ebp - 0x10918]
            //   e8????????           |                     

        $sequence_6 = { 8b4d08 e8???????? 50 e8???????? 83c40c 8b4dc8 }
            // n = 6, score = 100
            //   8b4d08               | mov                 ecx, dword ptr [ebp + 8]
            //   e8????????           |                     
            //   50                   | push                eax
            //   e8????????           |                     
            //   83c40c               | add                 esp, 0xc
            //   8b4dc8               | mov                 ecx, dword ptr [ebp - 0x38]

        $sequence_7 = { be???????? 8dbd80feffff f3a5 a4 6a15 8d8580feffff 50 }
            // n = 7, score = 100
            //   be????????           |                     
            //   8dbd80feffff         | lea                 edi, [ebp - 0x180]
            //   f3a5                 | rep movsd           dword ptr es:[edi], dword ptr [esi]
            //   a4                   | movsb               byte ptr es:[edi], byte ptr [esi]
            //   6a15                 | push                0x15
            //   8d8580feffff         | lea                 eax, [ebp - 0x180]
            //   50                   | push                eax

        $sequence_8 = { 6a00 6800000040 8d8dc8f8feff e8???????? 50 }
            // n = 5, score = 100
            //   6a00                 | push                0
            //   6800000040           | push                0x40000000
            //   8d8dc8f8feff         | lea                 ecx, [ebp - 0x10738]
            //   e8????????           |                     
            //   50                   | push                eax

        $sequence_9 = { 8bec 8b4d08 33c0 3b0cc5f86d0310 7427 40 83f82d }
            // n = 7, score = 100
            //   8bec                 | mov                 ebp, esp
            //   8b4d08               | mov                 ecx, dword ptr [ebp + 8]
            //   33c0                 | xor                 eax, eax
            //   3b0cc5f86d0310       | cmp                 ecx, dword ptr [eax*8 + 0x10036df8]
            //   7427                 | je                  0x29
            //   40                   | inc                 eax
            //   83f82d               | cmp                 eax, 0x2d

    condition:
        7 of them and filesize < 918528
}