rule win_kerrdown_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-04-08"
        version = "1"
        description = "Detects win.kerrdown."
        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.kerrdown"
        malpedia_rule_date = "20220405"
        malpedia_hash = "ecd38294bd47d5589be5cd5490dc8bb4804afc2a"
        malpedia_version = "20220411"
        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 = { ff15???????? 6a01 68???????? 68???????? 53 68???????? 6a00 }
            // n = 7, score = 200
            //   ff15????????         |                     
            //   6a01                 | push                1
            //   68????????           |                     
            //   68????????           |                     
            //   53                   | push                ebx
            //   68????????           |                     
            //   6a00                 | push                0

        $sequence_1 = { 50 e8???????? 8b3d???????? 83c40c 8b0d???????? 83ff10 }
            // n = 6, score = 200
            //   50                   | push                eax
            //   e8????????           |                     
            //   8b3d????????         |                     
            //   83c40c               | add                 esp, 0xc
            //   8b0d????????         |                     
            //   83ff10               | cmp                 edi, 0x10

        $sequence_2 = { e8???????? 8b442430 83c418 83f810 722f }
            // n = 5, score = 200
            //   e8????????           |                     
            //   8b442430             | mov                 eax, dword ptr [esp + 0x30]
            //   83c418               | add                 esp, 0x18
            //   83f810               | cmp                 eax, 0x10
            //   722f                 | jb                  0x31

        $sequence_3 = { 8d44241c 8bcc 6aff 6a00 c741140f000000 c7411000000000 }
            // n = 6, score = 200
            //   8d44241c             | lea                 eax, dword ptr [esp + 0x1c]
            //   8bcc                 | mov                 ecx, esp
            //   6aff                 | push                -1
            //   6a00                 | push                0
            //   c741140f000000       | mov                 dword ptr [ecx + 0x14], 0xf
            //   c7411000000000       | mov                 dword ptr [ecx + 0x10], 0

        $sequence_4 = { 64a300000000 8bf9 897ddc c745d800000000 33f6 c747140f000000 }
            // n = 6, score = 200
            //   64a300000000         | mov                 dword ptr fs:[0], eax
            //   8bf9                 | mov                 edi, ecx
            //   897ddc               | mov                 dword ptr [ebp - 0x24], edi
            //   c745d800000000       | mov                 dword ptr [ebp - 0x28], 0
            //   33f6                 | xor                 esi, esi
            //   c747140f000000       | mov                 dword ptr [edi + 0x14], 0xf

        $sequence_5 = { 03c2 3d???????? 762a ff750c 83ff10 }
            // n = 5, score = 200
            //   03c2                 | add                 eax, edx
            //   3d????????           |                     
            //   762a                 | jbe                 0x2c
            //   ff750c               | push                dword ptr [ebp + 0xc]
            //   83ff10               | cmp                 edi, 0x10

        $sequence_6 = { 8b45dc 85c0 0f8544ffffff 85f6 0f848f000000 33c0 }
            // n = 6, score = 200
            //   8b45dc               | mov                 eax, dword ptr [ebp - 0x24]
            //   85c0                 | test                eax, eax
            //   0f8544ffffff         | jne                 0xffffff4a
            //   85f6                 | test                esi, esi
            //   0f848f000000         | je                  0x95
            //   33c0                 | xor                 eax, eax

        $sequence_7 = { 8a01 41 884435e8 46 894de0 83fe04 7571 }
            // n = 7, score = 200
            //   8a01                 | mov                 al, byte ptr [ecx]
            //   41                   | inc                 ecx
            //   884435e8             | mov                 byte ptr [ebp + esi - 0x18], al
            //   46                   | inc                 esi
            //   894de0               | mov                 dword ptr [ebp - 0x20], ecx
            //   83fe04               | cmp                 esi, 4
            //   7571                 | jne                 0x73

        $sequence_8 = { 8a01 41 884435e8 46 }
            // n = 4, score = 200
            //   8a01                 | mov                 al, byte ptr [ecx]
            //   41                   | inc                 ecx
            //   884435e8             | mov                 byte ptr [ebp + esi - 0x18], al
            //   46                   | inc                 esi

        $sequence_9 = { ff750c 83ff10 ba???????? b8???????? 0f43d1 b9???????? 2bc2 }
            // n = 7, score = 200
            //   ff750c               | push                dword ptr [ebp + 0xc]
            //   83ff10               | cmp                 edi, 0x10
            //   ba????????           |                     
            //   b8????????           |                     
            //   0f43d1               | cmovae              edx, ecx
            //   b9????????           |                     
            //   2bc2                 | sub                 eax, edx

    condition:
        7 of them and filesize < 278528
}