rule win_yibackdoor_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        version = "1"
        description = "Detects win.yibackdoor."
        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.yibackdoor"
        malpedia_rule_date = "20260422"
        malpedia_hash = "a182e35da64e6d71cb55f125c4d4225196523f14"
        malpedia_version = "20260504"
        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 = { 84c9 75ef 458b4c1820 4d8bd8 418b741814 4c03cb 458bd6 }
            // n = 7, score = 100
            //   84c9                 | jmp                 0x1336
            //   75ef                 | cmp                 cl, 0x2e
            //   458b4c1820           | jmp                 0x1330
            //   4d8bd8               | dec                 eax
            //   418b741814           | mov                 ecx, edi
            //   4c03cb               | xor                 eax, eax
            //   458bd6               | dec                 esp

        $sequence_1 = { 418bd6 ffd0 3d02010000 752b 488b4d90 33d2 ff15???????? }
            // n = 7, score = 100
            //   418bd6               | sub                 edi, 1
            //   ffd0                 | jne                 0x12c4
            //   3d02010000           | inc                 bx
            //   752b                 | mov                 dword ptr [ecx + ebx], esi
            //   488b4d90             | dec                 eax
            //   33d2                 | mov                 ebx, dword ptr [esp + 8]
            //   ff15????????         |                     

        $sequence_2 = { 4883ec30 488bfa 418bf0 33d2 4c8bf1 33c9 }
            // n = 6, score = 100
            //   4883ec30             | mov                 eax, ebx
            //   488bfa               | inc                 edx
            //   418bf0               | mov                 eax, dword ptr [ebp + eax*4 - 0x35]
            //   33d2                 | mov                 al, byte ptr [ebp - 0x30]
            //   4c8bf1               | test                al, al
            //   33c9                 | jne                 0x18f7

        $sequence_3 = { 488d4da0 33d2 e8???????? 33d2 895da0 33c9 448d4baa }
            // n = 7, score = 100
            //   488d4da0             | dec                 eax
            //   33d2                 | cmp                 dword ptr [ebx + 0x18], edi
            //   e8????????           |                     
            //   33d2                 | jne                 0xd1b
            //   895da0               | cmp                 dword ptr [ebx + 8], 4
            //   33c9                 | jne                 0xdb8
            //   448d4baa             | dec                 ecx

        $sequence_4 = { 7406 8b4028 8945d7 44887c2420 c74424244632b25f c74424285f30c738 8b442424 }
            // n = 7, score = 100
            //   7406                 | and                 eax, 0xf
            //   8b4028               | movzx               edx, al
            //   8945d7               | dec                 esp
            //   44887c2420           | lea                 eax, [0x42ac]
            //   c74424244632b25f     | mov                 eax, edx
            //   c74424285f30c738     | and                 eax, 0xf
            //   8b442424             | inc                 edx

        $sequence_5 = { 488bc1 4885c9 7505 c3 4883c102 663911 75f7 }
            // n = 7, score = 100
            //   488bc1               | je                  0x847
            //   4885c9               | mov                 edx, 3
            //   7505                 | dec                 ebp
            //   c3                   | mov                 ecx, esi
            //   4883c102             | dec                 eax
            //   663911               | mov                 ecx, ebx
            //   75f7                 | inc                 esp

        $sequence_6 = { 488b15???????? 4803d7 48895110 488b09 e8???????? 488903 48897b08 }
            // n = 7, score = 100
            //   488b15????????       |                     
            //   4803d7               | inc                 esp
            //   48895110             | lea                 eax, [ecx - 0x2b]
            //   488b09               | test                dx, dx
            //   e8????????           |                     
            //   488903               | jne                 0x15a5
            //   48897b08             | cmp                 ecx, esi

        $sequence_7 = { c74513ac2aba60 895517 4489451b 89451f 895523 44894527 89452b }
            // n = 7, score = 100
            //   c74513ac2aba60       | dec                 eax
            //   895517               | mov                 ecx, dword ptr [ebp - 0x38]
            //   4489451b             | xor                 edx, edx
            //   89451f               | call                eax
            //   895523               | dec                 esp
            //   44894527             | lea                 ebx, [esp + 0x70]
            //   89452b               | inc                 eax

        $sequence_8 = { e8???????? 488bd0 488d4c2438 e8???????? 488b4c2468 e8???????? 40887c2420 }
            // n = 7, score = 100
            //   e8????????           |                     
            //   488bd0               | mov                 dword ptr [ebp - 0x1c], 0x706586c4
            //   488d4c2438           | mov                 dword ptr [ebp - 0x18], 0x7778ca84
            //   e8????????           |                     
            //   488b4c2468           | inc                 eax
            //   e8????????           |                     
            //   40887c2420           | mov                 byte ptr [ebp - 0x30], bh

        $sequence_9 = { 0f31 48c1e220 480bc2 8905???????? 488bcb 6901fd430300 bfc39e2600 }
            // n = 7, score = 100
            //   0f31                 | dec                 eax
            //   48c1e220             | cmp                 eax, -1
            //   480bc2               | je                  0x16be
            //   8905????????         |                     
            //   488bcb               | dec                 eax
            //   6901fd430300         | mov                 ecx, ebx
            //   bfc39e2600           | mov                 dword ptr [esp + 0x20], 3

    condition:
        7 of them and filesize < 147456
}