rule win_ragnarok_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.ragnarok."
        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.ragnarok"
        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 = { 8bc1 888c0dfcfeffff 99 f7fe 8a8415fcfdffff 88840dfcfcffff 41 }
            // n = 7, score = 200
            //   8bc1                 | mov                 eax, ecx
            //   888c0dfcfeffff       | mov                 byte ptr [ebp + ecx - 0x104], cl
            //   99                   | cdq                 
            //   f7fe                 | idiv                esi
            //   8a8415fcfdffff       | mov                 al, byte ptr [ebp + edx - 0x204]
            //   88840dfcfcffff       | mov                 byte ptr [ebp + ecx - 0x304], al
            //   41                   | inc                 ecx

        $sequence_1 = { 8a8090914200 8841fc 83ea01 75ec 43 836df801 75d5 }
            // n = 7, score = 200
            //   8a8090914200         | mov                 al, byte ptr [eax + 0x429190]
            //   8841fc               | mov                 byte ptr [ecx - 4], al
            //   83ea01               | sub                 edx, 1
            //   75ec                 | jne                 0xffffffee
            //   43                   | inc                 ebx
            //   836df801             | sub                 dword ptr [ebp - 8], 1
            //   75d5                 | jne                 0xffffffd7

        $sequence_2 = { 895d10 0fb691104b4300 8bcb c1e910 0fb6c9 }
            // n = 5, score = 200
            //   895d10               | mov                 dword ptr [ebp + 0x10], ebx
            //   0fb691104b4300       | movzx               edx, byte ptr [ecx + 0x434b10]
            //   8bcb                 | mov                 ecx, ebx
            //   c1e910               | shr                 ecx, 0x10
            //   0fb6c9               | movzx               ecx, cl

        $sequence_3 = { 23ca 8bd3 338decfeffff 03f9 0b95e8feffff 03b87cc14200 03bc0500ffffff }
            // n = 7, score = 200
            //   23ca                 | and                 ecx, edx
            //   8bd3                 | mov                 edx, ebx
            //   338decfeffff         | xor                 ecx, dword ptr [ebp - 0x114]
            //   03f9                 | add                 edi, ecx
            //   0b95e8feffff         | or                  edx, dword ptr [ebp - 0x118]
            //   03b87cc14200         | add                 edi, dword ptr [eax + 0x42c17c]
            //   03bc0500ffffff       | add                 edi, dword ptr [ebp + eax - 0x100]

        $sequence_4 = { 8855ff 83e900 7465 83e901 743d 83e901 }
            // n = 6, score = 200
            //   8855ff               | mov                 byte ptr [ebp - 1], dl
            //   83e900               | sub                 ecx, 0
            //   7465                 | je                  0x67
            //   83e901               | sub                 ecx, 1
            //   743d                 | je                  0x3f
            //   83e901               | sub                 ecx, 1

        $sequence_5 = { 03d9 13f8 8b8538fdffff 031cc580af4200 133cc584af4200 039cc5a4fdffff }
            // n = 6, score = 200
            //   03d9                 | add                 ebx, ecx
            //   13f8                 | adc                 edi, eax
            //   8b8538fdffff         | mov                 eax, dword ptr [ebp - 0x2c8]
            //   031cc580af4200       | add                 ebx, dword ptr [eax*8 + 0x42af80]
            //   133cc584af4200       | adc                 edi, dword ptr [eax*8 + 0x42af84]
            //   039cc5a4fdffff       | add                 ebx, dword ptr [ebp + eax*8 - 0x25c]

        $sequence_6 = { 85f6 7433 6a00 56 ff95c4feffff 56 ff95c8feffff }
            // n = 7, score = 200
            //   85f6                 | test                esi, esi
            //   7433                 | je                  0x35
            //   6a00                 | push                0
            //   56                   | push                esi
            //   ff95c4feffff         | call                dword ptr [ebp - 0x13c]
            //   56                   | push                esi
            //   ff95c8feffff         | call                dword ptr [ebp - 0x138]

        $sequence_7 = { 0fb689104b4300 33f9 c1e708 8b4dfc c1e908 0fb6c9 0fb689104b4300 }
            // n = 7, score = 200
            //   0fb689104b4300       | movzx               ecx, byte ptr [ecx + 0x434b10]
            //   33f9                 | xor                 edi, ecx
            //   c1e708               | shl                 edi, 8
            //   8b4dfc               | mov                 ecx, dword ptr [ebp - 4]
            //   c1e908               | shr                 ecx, 8
            //   0fb6c9               | movzx               ecx, cl
            //   0fb689104b4300       | movzx               ecx, byte ptr [ecx + 0x434b10]

        $sequence_8 = { 51 ff35???????? ffd3 6a17 ff35???????? 8bf0 e8???????? }
            // n = 7, score = 200
            //   51                   | push                ecx
            //   ff35????????         |                     
            //   ffd3                 | call                ebx
            //   6a17                 | push                0x17
            //   ff35????????         |                     
            //   8bf0                 | mov                 esi, eax
            //   e8????????           |                     

        $sequence_9 = { 57 8b7d0c 8d347d01000000 56 e8???????? 8bd8 83c404 }
            // n = 7, score = 200
            //   57                   | push                edi
            //   8b7d0c               | mov                 edi, dword ptr [ebp + 0xc]
            //   8d347d01000000       | lea                 esi, [edi*2 + 1]
            //   56                   | push                esi
            //   e8????????           |                     
            //   8bd8                 | mov                 ebx, eax
            //   83c404               | add                 esp, 4

    condition:
        7 of them and filesize < 483328
}