rule win_yibackdoor_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        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 = "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 = { 7508 488bca e8???????? 4c8bc0 488bd7 488bcb e8???????? }
            // n = 7, score = 100
            //   7508                 | je                  0xb95
            //   488bca               | cmp                 edx, 1
            //   e8????????           |                     
            //   4c8bc0               | je                  0xbb7
            //   488bd7               | inc                 ebp
            //   488bcb               | add                 edx, edi
            //   e8????????           |                     

        $sequence_1 = { 7526 488bca e8???????? 488945c8 488bc8 4885c0 }
            // n = 6, score = 100
            //   7526                 | mov                 edi, eax
            //   488bca               | dec                 eax
            //   e8????????           |                     
            //   488945c8             | mov                 ecx, ebx
            //   488bc8               | cmp                 dword ptr [ebp + 0x67], 0
            //   4885c0               | je                  0xcb0

        $sequence_2 = { 4d8bf0 33d2 488bd9 33c9 41b802f1f808 }
            // n = 5, score = 100
            //   4d8bf0               | jne                 0x1f9d
            //   33d2                 | inc                 esp
            //   488bd9               | cmp                 ebx, edi
            //   33c9                 | je                  0x1fdd
            //   41b802f1f808         | inc                 ecx

        $sequence_3 = { 480fa3ca 7218 80e95b 80f920 77d2 48b80508080201000000 480fa3c8 }
            // n = 7, score = 100
            //   480fa3ca             | dec                 eax
            //   7218                 | mov                 eax, dword ptr [ebx]
            //   80e95b               | dec                 eax
            //   80f920               | mov                 dword ptr [eax + ecx*8 - 8], esi
            //   77d2                 | dec                 eax
            //   48b80508080201000000     | mov    ecx, dword ptr [esp + 0x38]
            //   480fa3c8             | dec                 eax

        $sequence_4 = { 488bd0 488d4dd0 e8???????? 4c8b75d0 b301 eb02 32db }
            // n = 7, score = 100
            //   488bd0               | lea                 ecx, [ebp - 0x20]
            //   488d4dd0             | mov                 ebx, eax
            //   e8????????           |                     
            //   4c8b75d0             | test                eax, eax
            //   b301                 | jne                 0xbd9
            //   eb02                 | mov                 dword ptr [esi + 8], eax
            //   32db                 | dec                 eax

        $sequence_5 = { 4533c0 418bd7 488bcb ffd0 488d7608 488b06 }
            // n = 6, score = 100
            //   4533c0               | inc                 edx
            //   418bd7               | dec                 ecx
            //   488bcb               | cmp                 edx, edx
            //   ffd0                 | jne                 0x10f3
            //   488d7608             | dec                 eax
            //   488b06               | mov                 eax, dword ptr [ebp - 0x38]

        $sequence_6 = { 488905???????? 4c8d4d10 488d05c8ab0000 c744242840000000 }
            // n = 4, score = 100
            //   488905????????       |                     
            //   4c8d4d10             | jns                 0xcf9
            //   488d05c8ab0000       | inc                 ecx
            //   c744242840000000     | mov                 ebx, ecx

        $sequence_7 = { 440fb6fa 498bf1 458be0 488bf9 bbc39e2600 84d2 743a }
            // n = 7, score = 100
            //   440fb6fa             | dec                 eax
            //   498bf1               | mov                 eax, dword ptr [ebx]
            //   458be0               | xor                 edx, edx
            //   488bf9               | dec                 eax
            //   bbc39e2600           | mov                 dword ptr [esp + 0x20], eax
            //   84d2                 | inc                 ecx
            //   743a                 | call                edx

        $sequence_8 = { 488d4dc7 e8???????? 488b4daf e8???????? 40887d9f baa549af44 c745a3c149ce44 }
            // n = 7, score = 100
            //   488d4dc7             | dec                 eax
            //   e8????????           |                     
            //   488b4daf             | mov                 dword ptr [ebp - 8], 0
            //   e8????????           |                     
            //   40887d9f             | dec                 eax
            //   baa549af44           | mov                 dword ptr [ebp - 9], 0
            //   c745a3c149ce44       | inc                 ebp

        $sequence_9 = { 488d6c24a9 4881ec90000000 b8c57ac231 33c9 884dc7 baf46bc464 }
            // n = 6, score = 100
            //   488d6c24a9           | cmp                 ecx, 2
            //   4881ec90000000       | mov                 eax, dword ptr [esp + ecx*4 + 0x24]
            //   b8c57ac231           | xor                 eax, 0x14a0108b
            //   33c9                 | mov                 dword ptr [esp + ecx*4 + 0x24], eax
            //   884dc7               | dec                 eax
            //   baf46bc464           | inc                 ecx

    condition:
        7 of them and filesize < 147456
}