rule win_microbackdoor_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-07-11"
        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 = "20230705"
        malpedia_hash = "42d0574f4405bd7d2b154d321d345acb18834a41"
        malpedia_version = "20230715"
        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 = { 4533c9 488d542430 458d4103 488bcb 66c74424300501 }
            // n = 5, score = 100
            //   4533c9               | dec                 eax
            //   488d542430           | mov                 ecx, 0x80000002
            //   458d4103             | dec                 eax
            //   488bcb               | mov                 dword ptr [esp + 0x20], eax
            //   66c74424300501       | mov                 ebx, eax

        $sequence_1 = { 0f832f010000 ff15???????? e9???????? 8b5d0c 8d4dec }
            // n = 5, score = 100
            //   0f832f010000         | cmp                 dword ptr [ebp - 0x94], 2
            //   ff15????????         |                     
            //   e9????????           |                     
            //   8b5d0c               | jne                 0xbe
            //   8d4dec               | cmp                 dword ptr [ebp - 0xa0], 5

        $sequence_2 = { ff15???????? 488905???????? 4885c0 742f ff15???????? 3db7000000 7522 }
            // n = 7, score = 100
            //   ff15????????         |                     
            //   488905????????       |                     
            //   4885c0               | dec                 eax
            //   742f                 | test                eax, eax
            //   ff15????????         |                     
            //   3db7000000           | je                  0x31
            //   7522                 | cmp                 eax, 0xb7

        $sequence_3 = { ff15???????? eb06 ff15???????? 5b 5f }
            // n = 5, score = 100
            //   ff15????????         |                     
            //   eb06                 | test                eax, eax
            //   ff15????????         |                     
            //   5b                   | jne                 0x11
            //   5f                   | or                  eax, 0xffffffff

        $sequence_4 = { ff15???????? 33c0 e9???????? 83bd6cffffff02 0f85b1000000 83bd60ffffff05 0f86a4000000 }
            // n = 7, score = 100
            //   ff15????????         |                     
            //   33c0                 | jne                 0xc6
            //   e9????????           |                     
            //   83bd6cffffff02       | dec                 ebp
            //   0f85b1000000         | mov                 eax, esi
            //   83bd60ffffff05       | dec                 eax
            //   0f86a4000000         | mov                 eax, ebx

        $sequence_5 = { 8bf0 85f6 7504 33c0 eb79 8b3d???????? }
            // n = 6, score = 100
            //   8bf0                 | push                esi
            //   85f6                 | push                dword ptr [ebp + 8]
            //   7504                 | xor                 esi, esi
            //   33c0                 | test                eax, eax
            //   eb79                 | xor                 eax, eax
            //   8b3d????????         |                     

        $sequence_6 = { 85c0 0f8ea0000000 8d85f0feffff 50 53 e8???????? 85c0 }
            // n = 7, score = 100
            //   85c0                 | nop                 dword ptr [eax]
            //   0f8ea0000000         | cmp                 byte ptr [ebx + eax + 1], 0
            //   8d85f0feffff         | dec                 eax
            //   50                   | lea                 eax, [eax + 1]
            //   53                   | jne                 0xd
            //   e8????????           |                     
            //   85c0                 | lea                 edx, [eax + 1]

        $sequence_7 = { ff15???????? 8bd8 85c0 7514 ff15???????? 488d0d2f6c0000 }
            // n = 6, score = 100
            //   ff15????????         |                     
            //   8bd8                 | inc                 esp
            //   85c0                 | mov                 ecx, edi
            //   7514                 | inc                 ebp
            //   ff15????????         |                     
            //   488d0d2f6c0000       | xor                 eax, eax

        $sequence_8 = { 8b5d0c 40 56 33f6 }
            // n = 4, score = 100
            //   8b5d0c               | jbe                 0xbe
            //   40                   | mov                 eax, dword ptr [ebp - 0x234]
            //   56                   | pop                 ecx
            //   33f6                 | pop                 ecx

        $sequence_9 = { e8???????? 8b85ccfdffff 59 59 85c0 7505 83c8ff }
            // n = 7, score = 100
            //   e8????????           |                     
            //   8b85ccfdffff         | dec                 esp
            //   59                   | sub                 eax, ebx
            //   59                   | nop                 word ptr [eax + eax]
            //   85c0                 | je                  0x6d
            //   7505                 | dec                 eax
            //   83c8ff               | or                  eax, 0xffffffff

        $sequence_10 = { 4439a5a8000000 0f85b9000000 4d8bc6 488bc3 4c2bc3 66660f1f840000000000 }
            // n = 6, score = 100
            //   4439a5a8000000       | inc                 ebp
            //   0f85b9000000         | xor                 ecx, ecx
            //   4d8bc6               | dec                 eax
            //   488bc3               | lea                 edx, [esp + 0x30]
            //   4c2bc3               | inc                 ebp
            //   66660f1f840000000000     | lea    eax, [ecx + 3]

        $sequence_11 = { 7514 8d4201 488b9c24f0000000 4881c4e0000000 }
            // n = 4, score = 100
            //   7514                 | test                eax, eax
            //   8d4201               | jne                 0x1a
            //   488b9c24f0000000     | dec                 eax
            //   4881c4e0000000       | lea                 ecx, [0x6c2f]

        $sequence_12 = { 488d1543520000 448bcf 4533c0 48c7c102000080 4889442420 }
            // n = 5, score = 100
            //   488d1543520000       | mov                 dword ptr [esp + 0x28], 0x7ff
            //   448bcf               | dec                 esp
            //   4533c0               | mov                 dword ptr [esp + 0x20], esi
            //   48c7c102000080       | dec                 eax
            //   4889442420           | lea                 edx, [0x5243]

        $sequence_13 = { 56 ff7508 ff15???????? a1???????? 33f6 8b1d???????? 85c0 }
            // n = 7, score = 100
            //   56                   | dec                 eax
            //   ff7508               | add                 esp, 0xe0
            //   ff15????????         |                     
            //   a1????????           |                     
            //   33f6                 | inc                 esp
            //   8b1d????????         |                     
            //   85c0                 | cmp                 dword ptr [ebp + 0xa8], esp

        $sequence_14 = { b9e9fd0000 c7442428ff070000 4c89742420 ff15???????? }
            // n = 4, score = 100
            //   b9e9fd0000           | dec                 eax
            //   c7442428ff070000     | lea                 ecx, [0x640e]
            //   4c89742420           | mov                 ecx, 0xfde9
            //   ff15????????         |                     

        $sequence_15 = { 8bd0 e8???????? 8b542468 488d0d0e640000 e8???????? }
            // n = 5, score = 100
            //   8bd0                 | jne                 0x24
            //   e8????????           |                     
            //   8b542468             | mov                 edx, eax
            //   488d0d0e640000       | mov                 edx, dword ptr [esp + 0x68]
            //   e8????????           |                     

    condition:
        7 of them and filesize < 123904
}