rule win_kerrdown_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2020-05-30"
        version = "1"
        description = "autogenerated rule brought to you by yara-signator"
        tool = "yara-signator v0.4.0"
        tool_config = "callsandjumps;datarefs;binvalue"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.kerrdown"
        malpedia_rule_date = "20200529"
        malpedia_hash = "92c362319514e5a6da26204961446caa3a8b32a8"
        malpedia_version = "20200529"
        malpedia_license = "CC BY-NC-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 / approach 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 = { 75f3 57 8d7bff 8a4701 8d7f01 84c0 75f6 }
            // n = 7, score = 200
            //   75f3                 | jne                 0xfffffff5
            //   57                   | push                edi
            //   8d7bff               | lea                 edi, [ebx - 1]
            //   8a4701               | mov                 al, byte ptr [edi + 1]
            //   8d7f01               | lea                 edi, [edi + 1]
            //   84c0                 | test                al, al
            //   75f6                 | jne                 0xfffffff8

        $sequence_1 = { 33c4 8944241c 6807800000 ff15???????? e8???????? 8d4c2404 }
            // n = 6, score = 200
            //   33c4                 | xor                 eax, esp
            //   8944241c             | mov                 dword ptr [esp + 0x1c], eax
            //   6807800000           | push                0x8007
            //   ff15????????         |                     
            //   e8????????           |                     
            //   8d4c2404             | lea                 ecx, [esp + 4]

        $sequence_2 = { 3bde 7ced 8bc7 8b4df4 64890d00000000 59 5f }
            // n = 7, score = 200
            //   3bde                 | cmp                 ebx, esi
            //   7ced                 | jl                  0xffffffef
            //   8bc7                 | mov                 eax, edi
            //   8b4df4               | mov                 ecx, dword ptr [ebp - 0xc]
            //   64890d00000000       | mov                 dword ptr fs:[0], ecx
            //   59                   | pop                 ecx
            //   5f                   | pop                 edi

        $sequence_3 = { 6683f87f 8d642408 0f854d0d0000 eb00 }
            // n = 4, score = 200
            //   6683f87f             | cmp                 ax, 0x7f
            //   8d642408             | lea                 esp, [esp + 8]
            //   0f854d0d0000         | jne                 0xd53
            //   eb00                 | jmp                 2

        $sequence_4 = { 50 e8???????? 88441de8 43 }
            // n = 4, score = 200
            //   50                   | push                eax
            //   e8????????           |                     
            //   88441de8             | mov                 byte ptr [ebp + ebx - 0x18], al
            //   43                   | inc                 ebx

        $sequence_5 = { c745f800000000 83feff 7438 6a00 8d45f8 }
            // n = 5, score = 200
            //   c745f800000000       | mov                 dword ptr [ebp - 8], 0
            //   83feff               | cmp                 esi, -1
            //   7438                 | je                  0x3a
            //   6a00                 | push                0
            //   8d45f8               | lea                 eax, [ebp - 8]

        $sequence_6 = { 83c408 8bd3 2bd6 8a0e 8d7601 884c32ff }
            // n = 6, score = 200
            //   83c408               | add                 esp, 8
            //   8bd3                 | mov                 edx, ebx
            //   2bd6                 | sub                 edx, esi
            //   8a0e                 | mov                 cl, byte ptr [esi]
            //   8d7601               | lea                 esi, [esi + 1]
            //   884c32ff             | mov                 byte ptr [edx + esi - 1], cl

        $sequence_7 = { 68???????? 53 68???????? 6a00 ff15???????? }
            // n = 5, score = 200
            //   68????????           |                     
            //   53                   | push                ebx
            //   68????????           |                     
            //   6a00                 | push                0
            //   ff15????????         |                     

        $sequence_8 = { e8???????? 8d4c2404 e8???????? 83ec18 8d44241c 8bcc 6aff }
            // n = 7, score = 200
            //   e8????????           |                     
            //   8d4c2404             | lea                 ecx, [esp + 4]
            //   e8????????           |                     
            //   83ec18               | sub                 esp, 0x18
            //   8d44241c             | lea                 eax, [esp + 0x1c]
            //   8bcc                 | mov                 ecx, esp
            //   6aff                 | push                -1

        $sequence_9 = { c745f800000000 83feff 7438 6a00 }
            // n = 4, score = 200
            //   c745f800000000       | mov                 dword ptr [ebp - 8], 0
            //   83feff               | cmp                 esi, -1
            //   7438                 | je                  0x3a
            //   6a00                 | push                0

    condition:
        7 of them and filesize < 278528
}