rule win_datper_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.datper."
        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.datper"
        malpedia_rule_date = "20260916"
        malpedia_hash = "53a643781c18e08f4a50949af60172d837a0b6f6"
        malpedia_version = "20260917"
        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 = { 03db 83c314 8bcb 8b55d4 a1???????? e8???????? 33c0 }
            // n = 7, score = 200
            //   03db                 | add                 ebx, ebx
            //   83c314               | add                 ebx, 0x14
            //   8bcb                 | mov                 ecx, ebx
            //   8b55d4               | mov                 edx, dword ptr [ebp - 0x2c]
            //   a1????????           |                     
            //   e8????????           |                     
            //   33c0                 | xor                 eax, eax

        $sequence_1 = { 55 8bec 6a00 53 56 8bf1 8bd8 }
            // n = 7, score = 200
            //   55                   | push                ebp
            //   8bec                 | mov                 ebp, esp
            //   6a00                 | push                0
            //   53                   | push                ebx
            //   56                   | push                esi
            //   8bf1                 | mov                 esi, ecx
            //   8bd8                 | mov                 ebx, eax

        $sequence_2 = { 33f6 33c0 89430c 33c0 894310 0fb74304 662db1d7 }
            // n = 7, score = 200
            //   33f6                 | xor                 esi, esi
            //   33c0                 | xor                 eax, eax
            //   89430c               | mov                 dword ptr [ebx + 0xc], eax
            //   33c0                 | xor                 eax, eax
            //   894310               | mov                 dword ptr [ebx + 0x10], eax
            //   0fb74304             | movzx               eax, word ptr [ebx + 4]
            //   662db1d7             | sub                 ax, 0xd7b1

        $sequence_3 = { 68???????? 53 ff15???????? 83f801 1bc0 40 84c0 }
            // n = 7, score = 200
            //   68????????           |                     
            //   53                   | push                ebx
            //   ff15????????         |                     
            //   83f801               | cmp                 eax, 1
            //   1bc0                 | sbb                 eax, eax
            //   40                   | inc                 eax
            //   84c0                 | test                al, al

        $sequence_4 = { 0fb64de2 c1e106 0fb65de3 0acb 884c1001 8345f003 3b75e8 }
            // n = 7, score = 200
            //   0fb64de2             | movzx               ecx, byte ptr [ebp - 0x1e]
            //   c1e106               | shl                 ecx, 6
            //   0fb65de3             | movzx               ebx, byte ptr [ebp - 0x1d]
            //   0acb                 | or                  cl, bl
            //   884c1001             | mov                 byte ptr [eax + edx + 1], cl
            //   8345f003             | add                 dword ptr [ebp - 0x10], 3
            //   3b75e8               | cmp                 esi, dword ptr [ebp - 0x18]

        $sequence_5 = { e8???????? 8d55e8 e8???????? ff75f8 68???????? }
            // n = 5, score = 200
            //   e8????????           |                     
            //   8d55e8               | lea                 edx, [ebp - 0x18]
            //   e8????????           |                     
            //   ff75f8               | push                dword ptr [ebp - 8]
            //   68????????           |                     

        $sequence_6 = { 8d45e8 33c9 ba14000000 e8???????? 66c745e80100 8d043e 0fb600 }
            // n = 7, score = 200
            //   8d45e8               | lea                 eax, [ebp - 0x18]
            //   33c9                 | xor                 ecx, ecx
            //   ba14000000           | mov                 edx, 0x14
            //   e8????????           |                     
            //   66c745e80100         | mov                 word ptr [ebp - 0x18], 1
            //   8d043e               | lea                 eax, [esi + edi]
            //   0fb600               | movzx               eax, byte ptr [eax]

        $sequence_7 = { 81c404f0ffff 50 48 75f6 8b45fc 81c4d8f6ffff }
            // n = 6, score = 200
            //   81c404f0ffff         | add                 esp, 0xfffff004
            //   50                   | push                eax
            //   48                   | dec                 eax
            //   75f6                 | jne                 0xfffffff8
            //   8b45fc               | mov                 eax, dword ptr [ebp - 4]
            //   81c4d8f6ffff         | add                 esp, 0xfffff6d8

        $sequence_8 = { 894dfc 33c9 894df8 4a 85d2 7c39 }
            // n = 6, score = 200
            //   894dfc               | mov                 dword ptr [ebp - 4], ecx
            //   33c9                 | xor                 ecx, ecx
            //   894df8               | mov                 dword ptr [ebp - 8], ecx
            //   4a                   | dec                 edx
            //   85d2                 | test                edx, edx
            //   7c39                 | jl                  0x3b

        $sequence_9 = { 807dfd00 7423 6a00 6800318080 6a00 8b4514 50 }
            // n = 7, score = 200
            //   807dfd00             | cmp                 byte ptr [ebp - 3], 0
            //   7423                 | je                  0x25
            //   6a00                 | push                0
            //   6800318080           | push                0x80803100
            //   6a00                 | push                0
            //   8b4514               | mov                 eax, dword ptr [ebp + 0x14]
            //   50                   | push                eax

    condition:
        7 of them and filesize < 253952
}