rule win_chaperone_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        version = "1"
        description = "Detects win.chaperone."
        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.chaperone"
        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 = { 0f8557010000 488dbc2428050000 488d35aca90100 b92a000000 f3a4 488d8c2428050000 e8???????? }
            // n = 7, score = 100
            //   0f8557010000         | mov                 eax, 0x1f
            //   488dbc2428050000     | dec                 eax
            //   488d35aca90100       | mov                 ecx, dword ptr [esp + 0x40]
            //   b92a000000           | dec                 eax
            //   f3a4                 | add                 ecx, 5
            //   488d8c2428050000     | inc                 ecx
            //   e8????????           |                     

        $sequence_1 = { 488d1591c80000 448bc7 8bcf ff15???????? }
            // n = 4, score = 100
            //   488d1591c80000       | dec                 eax
            //   448bc7               | mov                 dword ptr [esp + 0x4b8], eax
            //   8bcf                 | dec                 eax
            //   ff15????????         |                     

        $sequence_2 = { e8???????? 4863942440010000 4c8d442430 488b4c2420 e8???????? 488b8c2458010000 4833cc }
            // n = 7, score = 100
            //   e8????????           |                     
            //   4863942440010000     | cmp                 dword ptr [esp + 0x4938], 0
            //   4c8d442430           | je                  0xccf
            //   488b4c2420           | mov                 dword ptr [esp + 0x4940], 0
            //   e8????????           |                     
            //   488b8c2458010000     | xor                 edx, edx
            //   4833cc               | mov                 ecx, 0x1f0001

        $sequence_3 = { 488d7b58 be06000000 488d05d5bd0100 483947f0 }
            // n = 4, score = 100
            //   488d7b58             | jmp                 0x6db
            //   be06000000           | dec                 eax
            //   488d05d5bd0100       | mov                 ecx, dword ptr [esp + 0x30]
            //   483947f0             | dec                 eax

        $sequence_4 = { 89442424 448b442424 33d2 b900040000 ff15???????? 4889442470 48837c247000 }
            // n = 7, score = 100
            //   89442424             | jne                 0x6c8
            //   448b442424           | dec                 eax
            //   33d2                 | lea                 edi, [esp + 0x108]
            //   b900040000           | dec                 eax
            //   ff15????????         |                     
            //   4889442470           | lea                 esi, [0x8c3b]
            //   48837c247000         | mov                 ecx, 0x1d

        $sequence_5 = { 837c243000 740a 83bc24a00700001f 7545 488d442434 4889442428 8b8424a0070000 }
            // n = 7, score = 100
            //   837c243000           | mov                 dword ptr [esp + 0x48], 1
            //   740a                 | jmp                 0xb49
            //   83bc24a00700001f     | dec                 eax
            //   7545                 | lea                 edx, [esp + 0x50]
            //   488d442434           | dec                 eax
            //   4889442428           | lea                 ecx, [esp + 0x80]
            //   8b8424a0070000       | dec                 eax

        $sequence_6 = { 48898424c0020000 837c243400 746b 4c8b842490000000 8b542434 488b8c24c0020000 e8???????? }
            // n = 7, score = 100
            //   48898424c0020000     | test                eax, eax
            //   837c243400           | je                  0x58a
            //   746b                 | mov                 dword ptr [esp + 0x260], 1
            //   4c8b842490000000     | jmp                 0x58f
            //   8b542434             | dec                 eax
            //   488b8c24c0020000     | lea                 ecx, [esp + 0x8280]
            //   e8????????           |                     

        $sequence_7 = { 488d8c24b0440000 e8???????? 4885c0 0f8441030000 488d8c24b0440000 e8???????? }
            // n = 6, score = 100
            //   488d8c24b0440000     | mov                 ebx, eax
            //   e8????????           |                     
            //   4885c0               | mov                 eax, dword ptr [esp + 0x20]
            //   0f8441030000         | mov                 ecx, dword ptr [esp + 0x48]
            //   488d8c24b0440000     | sub                 ecx, eax
            //   e8????????           |                     

        $sequence_8 = { 4533c0 33d2 33c9 e8???????? 4c8d050c0a0100 498bd5 488bcf }
            // n = 7, score = 100
            //   4533c0               | lea                 ecx, [esp + 0x88]
            //   33d2                 | dec                 esp
            //   33c9                 | mov                 dword ptr [esp + 0xe0], ebx
            //   e8????????           |                     
            //   4c8d050c0a0100       | dec                 eax
            //   498bd5               | mov                 edx, eax
            //   488bcf               | dec                 eax

        $sequence_9 = { 4889442450 488b8424a8000000 4889442448 488b8424a0000000 4889442440 }
            // n = 5, score = 100
            //   4889442450           | mov                 byte ptr [esp + 0x295], 0x49
            //   488b8424a8000000     | mov                 byte ptr [esp + 0x296], 0x4c
            //   4889442448           | mov                 byte ptr [esp + 0x297], 0x11
            //   488b8424a0000000     | mov                 dword ptr [esp + 0x30], 0
            //   4889442440           | mov                 byte ptr [esp + 0x296], 0x4c

    condition:
        7 of them and filesize < 373760
}