rule win_kerrdown_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        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 = "20260422"
        malpedia_hash = "a182e35da64e6d71cb55f125c4d4225196523f14"
        malpedia_version = "20260504"
        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 = { 83feff 7438 6a00 8d45f8 50 68004a0000 68???????? }
            // n = 7, score = 200
            //   83feff               | cmp                 esi, -1
            //   7438                 | je                  0x3a
            //   6a00                 | push                0
            //   8d45f8               | lea                 eax, [ebp - 8]
            //   50                   | push                eax
            //   68004a0000           | push                0x4a00
            //   68????????           |                     

        $sequence_1 = { e8???????? 8b3d???????? 8b0d???????? 85f6 743f }
            // n = 5, score = 200
            //   e8????????           |                     
            //   8b3d????????         |                     
            //   8b0d????????         |                     
            //   85f6                 | test                esi, esi
            //   743f                 | je                  0x41

        $sequence_2 = { f3a5 68???????? 66a5 ff15???????? 5f 85c0 7543 }
            // n = 7, score = 200
            //   f3a5                 | rep movsd           dword ptr es:[edi], dword ptr [esi]
            //   68????????           |                     
            //   66a5                 | movsw               word ptr es:[edi], word ptr [esi]
            //   ff15????????         |                     
            //   5f                   | pop                 edi
            //   85c0                 | test                eax, eax
            //   7543                 | jne                 0x45

        $sequence_3 = { ff15???????? e8???????? 8d4c2404 e8???????? 83ec18 }
            // n = 5, score = 200
            //   ff15????????         |                     
            //   e8????????           |                     
            //   8d4c2404             | lea                 ecx, [esp + 4]
            //   e8????????           |                     
            //   83ec18               | sub                 esp, 0x18

        $sequence_4 = { 8d45f8 50 68004a0000 68???????? 56 ff15???????? }
            // n = 6, score = 200
            //   8d45f8               | lea                 eax, [ebp - 8]
            //   50                   | push                eax
            //   68004a0000           | push                0x4a00
            //   68????????           |                     
            //   56                   | push                esi
            //   ff15????????         |                     

        $sequence_5 = { 8a441de8 83ec08 8845ec 8d45ec 50 }
            // n = 5, score = 200
            //   8a441de8             | mov                 al, byte ptr [ebp + ebx - 0x18]
            //   83ec08               | sub                 esp, 8
            //   8845ec               | mov                 byte ptr [ebp - 0x14], al
            //   8d45ec               | lea                 eax, [ebp - 0x14]
            //   50                   | push                eax

        $sequence_6 = { c745fc00000000 ff7518 6a00 ff15???????? }
            // n = 4, score = 200
            //   c745fc00000000       | mov                 dword ptr [ebp - 4], 0
            //   ff7518               | push                dword ptr [ebp + 0x18]
            //   6a00                 | push                0
            //   ff15????????         |                     

        $sequence_7 = { 0f848f000000 33c0 83f804 0f83a2000000 c64405e800 40 }
            // n = 6, score = 200
            //   0f848f000000         | je                  0x95
            //   33c0                 | xor                 eax, eax
            //   83f804               | cmp                 eax, 4
            //   0f83a2000000         | jae                 0xa8
            //   c64405e800           | mov                 byte ptr [ebp + eax - 0x18], 0
            //   40                   | inc                 eax

        $sequence_8 = { ddd8 db2d???????? b802000000 833d????????00 0f85400a0000 }
            // n = 5, score = 200
            //   ddd8                 | fstp                st(0)
            //   db2d????????         |                     
            //   b802000000           | mov                 eax, 2
            //   833d????????00       |                     
            //   0f85400a0000         | jne                 0xa46

        $sequence_9 = { 68???????? 56 ff15???????? 56 ff15???????? 6a01 68???????? }
            // n = 7, score = 200
            //   68????????           |                     
            //   56                   | push                esi
            //   ff15????????         |                     
            //   56                   | push                esi
            //   ff15????????         |                     
            //   6a01                 | push                1
            //   68????????           |                     

    condition:
        7 of them and filesize < 278528
}