rule win_kerrdown_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-03-28"
        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 = "20230328"
        malpedia_hash = "9d2d75cef573c1c2d861f5197df8f563b05a305d"
        malpedia_version = "20230407"
        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 = { 2bc8 83f904 722b 83f923 772b 8bc8 51 }
            // n = 7, score = 200
            //   2bc8                 | sub                 ecx, eax
            //   83f904               | cmp                 ecx, 4
            //   722b                 | jb                  0x2d
            //   83f923               | cmp                 ecx, 0x23
            //   772b                 | ja                  0x2d
            //   8bc8                 | mov                 ecx, eax
            //   51                   | push                ecx

        $sequence_1 = { 8b41fc 3bc1 732d 2bc8 83f904 722b 83f923 }
            // n = 7, score = 200
            //   8b41fc               | mov                 eax, dword ptr [ecx - 4]
            //   3bc1                 | cmp                 eax, ecx
            //   732d                 | jae                 0x2f
            //   2bc8                 | sub                 ecx, eax
            //   83f904               | cmp                 ecx, 4
            //   722b                 | jb                  0x2d
            //   83f923               | cmp                 ecx, 0x23

        $sequence_2 = { 0f854d0d0000 eb00 f30f7e442404 660f2815???????? 660f28c8 660f28f8 }
            // n = 6, score = 200
            //   0f854d0d0000         | jne                 0xd53
            //   eb00                 | jmp                 2
            //   f30f7e442404         | movq                xmm0, qword ptr [esp + 4]
            //   660f2815????????     |                     
            //   660f28c8             | movapd              xmm1, xmm0
            //   660f28f8             | movapd              xmm7, xmm0

        $sequence_3 = { c60100 e8???????? e8???????? 8b442430 }
            // n = 4, score = 200
            //   c60100               | mov                 byte ptr [ecx], 0
            //   e8????????           |                     
            //   e8????????           |                     
            //   8b442430             | mov                 eax, dword ptr [esp + 0x30]

        $sequence_4 = { 7cec 8b4de0 33f6 8b45dc }
            // n = 4, score = 200
            //   7cec                 | jl                  0xffffffee
            //   8b4de0               | mov                 ecx, dword ptr [ebp - 0x20]
            //   33f6                 | xor                 esi, esi
            //   8b45dc               | mov                 eax, dword ptr [ebp - 0x24]

        $sequence_5 = { 33f6 c747140f000000 b8cd220000 837f1410 }
            // n = 4, score = 200
            //   33f6                 | xor                 esi, esi
            //   c747140f000000       | mov                 dword ptr [edi + 0x14], 0xf
            //   b8cd220000           | mov                 eax, 0x22cd
            //   837f1410             | cmp                 dword ptr [edi + 0x14], 0x10

        $sequence_6 = { e8???????? 8b442430 83c418 83f810 722f 8b4c2404 }
            // n = 6, score = 200
            //   e8????????           |                     
            //   8b442430             | mov                 eax, dword ptr [esp + 0x30]
            //   83c418               | add                 esp, 0x18
            //   83f810               | cmp                 eax, 0x10
            //   722f                 | jb                  0x31
            //   8b4c2404             | mov                 ecx, dword ptr [esp + 4]

        $sequence_7 = { 83c40c 8b0d???????? 83ff10 8935???????? b8???????? }
            // n = 5, score = 200
            //   83c40c               | add                 esp, 0xc
            //   8b0d????????         |                     
            //   83ff10               | cmp                 edi, 0x10
            //   8935????????         |                     
            //   b8????????           |                     

        $sequence_8 = { 8b3d???????? 83c40c 8b0d???????? 83ff10 8935???????? b8???????? }
            // n = 6, score = 200
            //   8b3d????????         |                     
            //   83c40c               | add                 esp, 0xc
            //   8b0d????????         |                     
            //   83ff10               | cmp                 edi, 0x10
            //   8935????????         |                     
            //   b8????????           |                     

        $sequence_9 = { 8a45eb 243f 884de5 02c2 33f6 8845e6 0fb64435e4 }
            // n = 7, score = 200
            //   8a45eb               | mov                 al, byte ptr [ebp - 0x15]
            //   243f                 | and                 al, 0x3f
            //   884de5               | mov                 byte ptr [ebp - 0x1b], cl
            //   02c2                 | add                 al, dl
            //   33f6                 | xor                 esi, esi
            //   8845e6               | mov                 byte ptr [ebp - 0x1a], al
            //   0fb64435e4           | movzx               eax, byte ptr [ebp + esi - 0x1c]

    condition:
        7 of them and filesize < 278528
}