rule win_koadic_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2021-06-10"
        version = "1"
        description = "Detects win.koadic."
        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.koadic"
        malpedia_rule_date = "20210604"
        malpedia_hash = "be09d5d71e77373c0f538068be31a2ad4c69cfbd"
        malpedia_version = "20210616"
        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 = { 81e6ff000000 c1e908 330cb548154100 0fb67007 33f1 81e6ff000000 }
            // n = 6, score = 100
            //   81e6ff000000         | and                 esi, 0xff
            //   c1e908               | shr                 ecx, 8
            //   330cb548154100       | xor                 ecx, dword ptr [esi*4 + 0x411548]
            //   0fb67007             | movzx               esi, byte ptr [eax + 7]
            //   33f1                 | xor                 esi, ecx
            //   81e6ff000000         | and                 esi, 0xff

        $sequence_1 = { ff15???????? 89450c 83f8ff 7466 53 56 57 }
            // n = 7, score = 100
            //   ff15????????         |                     
            //   89450c               | mov                 dword ptr [ebp + 0xc], eax
            //   83f8ff               | cmp                 eax, -1
            //   7466                 | je                  0x68
            //   53                   | push                ebx
            //   56                   | push                esi
            //   57                   | push                edi

        $sequence_2 = { 7515 6a00 ff75fc ff75fc 683d330000 }
            // n = 5, score = 100
            //   7515                 | jne                 0x17
            //   6a00                 | push                0
            //   ff75fc               | push                dword ptr [ebp - 4]
            //   ff75fc               | push                dword ptr [ebp - 4]
            //   683d330000           | push                0x333d

        $sequence_3 = { 56 e8???????? 8bf8 85ff 75b9 8b4624 }
            // n = 6, score = 100
            //   56                   | push                esi
            //   e8????????           |                     
            //   8bf8                 | mov                 edi, eax
            //   85ff                 | test                edi, edi
            //   75b9                 | jne                 0xffffffbb
            //   8b4624               | mov                 eax, dword ptr [esi + 0x24]

        $sequence_4 = { 6aff e8???????? c3 55 8bec 837d0800 56 }
            // n = 7, score = 100
            //   6aff                 | push                -1
            //   e8????????           |                     
            //   c3                   | ret                 
            //   55                   | push                ebp
            //   8bec                 | mov                 ebp, esp
            //   837d0800             | cmp                 dword ptr [ebp + 8], 0
            //   56                   | push                esi

        $sequence_5 = { 85c0 740b 897e08 8b3f 85ff 75e6 eb39 }
            // n = 7, score = 100
            //   85c0                 | test                eax, eax
            //   740b                 | je                  0xd
            //   897e08               | mov                 dword ptr [esi + 8], edi
            //   8b3f                 | mov                 edi, dword ptr [edi]
            //   85ff                 | test                edi, edi
            //   75e6                 | jne                 0xffffffe8
            //   eb39                 | jmp                 0x3b

        $sequence_6 = { 03f7 8b0e 03f7 8b16 03f7 895508 }
            // n = 6, score = 100
            //   03f7                 | add                 esi, edi
            //   8b0e                 | mov                 ecx, dword ptr [esi]
            //   03f7                 | add                 esi, edi
            //   8b16                 | mov                 edx, dword ptr [esi]
            //   03f7                 | add                 esi, edi
            //   895508               | mov                 dword ptr [ebp + 8], edx

        $sequence_7 = { c20800 b801000000 c20800 85c0 }
            // n = 4, score = 100
            //   c20800               | ret                 8
            //   b801000000           | mov                 eax, 1
            //   c20800               | ret                 8
            //   85c0                 | test                eax, eax

        $sequence_8 = { 7417 8bc3 99 3bd1 7c10 7f06 }
            // n = 6, score = 100
            //   7417                 | je                  0x19
            //   8bc3                 | mov                 eax, ebx
            //   99                   | cdq                 
            //   3bd1                 | cmp                 edx, ecx
            //   7c10                 | jl                  0x12
            //   7f06                 | jg                  8

        $sequence_9 = { 8bd3 8bc6 2bd6 8da42400000000 8a08 880c02 }
            // n = 6, score = 100
            //   8bd3                 | mov                 edx, ebx
            //   8bc6                 | mov                 eax, esi
            //   2bd6                 | sub                 edx, esi
            //   8da42400000000       | lea                 esp, dword ptr [esp]
            //   8a08                 | mov                 cl, byte ptr [eax]
            //   880c02               | mov                 byte ptr [edx + eax], cl

    condition:
        7 of them and filesize < 180224
}