rule win_chches_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        version = "1"
        description = "Detects win.chches."
        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.chches"
        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 = { 745a 50 8b4660 ffd0 8b0e }
            // n = 5, score = 200
            //   745a                 | je                  0x5c
            //   50                   | push                eax
            //   8b4660               | mov                 eax, dword ptr [esi + 0x60]
            //   ffd0                 | call                eax
            //   8b0e                 | mov                 ecx, dword ptr [esi]

        $sequence_1 = { 8b550c 8b4508 8b8ec0000000 53 6880000000 52 53 }
            // n = 7, score = 200
            //   8b550c               | mov                 edx, dword ptr [ebp + 0xc]
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   8b8ec0000000         | mov                 ecx, dword ptr [esi + 0xc0]
            //   53                   | push                ebx
            //   6880000000           | push                0x80
            //   52                   | push                edx
            //   53                   | push                ebx

        $sequence_2 = { 8bf0 85f6 7404 c60600 46 803b00 7424 }
            // n = 7, score = 200
            //   8bf0                 | mov                 esi, eax
            //   85f6                 | test                esi, esi
            //   7404                 | je                  6
            //   c60600               | mov                 byte ptr [esi], 0
            //   46                   | inc                 esi
            //   803b00               | cmp                 byte ptr [ebx], 0
            //   7424                 | je                  0x26

        $sequence_3 = { 3bc3 7412 8b5644 50 53 ffd2 50 }
            // n = 7, score = 200
            //   3bc3                 | cmp                 eax, ebx
            //   7412                 | je                  0x14
            //   8b5644               | mov                 edx, dword ptr [esi + 0x44]
            //   50                   | push                eax
            //   53                   | push                ebx
            //   ffd2                 | call                edx
            //   50                   | push                eax

        $sequence_4 = { 33ff 33c0 81c61d051101 897df0 8945ec 3bcf }
            // n = 6, score = 200
            //   33ff                 | xor                 edi, edi
            //   33c0                 | xor                 eax, eax
            //   81c61d051101         | add                 esi, 0x111051d
            //   897df0               | mov                 dword ptr [ebp - 0x10], edi
            //   8945ec               | mov                 dword ptr [ebp - 0x14], eax
            //   3bcf                 | cmp                 ecx, edi

        $sequence_5 = { 746f 50 8b4664 ffd0 8b4c3bfc 8b4910 03c0 }
            // n = 7, score = 200
            //   746f                 | je                  0x71
            //   50                   | push                eax
            //   8b4664               | mov                 eax, dword ptr [esi + 0x64]
            //   ffd0                 | call                eax
            //   8b4c3bfc             | mov                 ecx, dword ptr [ebx + edi - 4]
            //   8b4910               | mov                 ecx, dword ptr [ecx + 0x10]
            //   03c0                 | add                 eax, eax

        $sequence_6 = { 8b45fc 8903 8b4d10 8b45f4 894b08 8b97c4000000 8b4df0 }
            // n = 7, score = 200
            //   8b45fc               | mov                 eax, dword ptr [ebp - 4]
            //   8903                 | mov                 dword ptr [ebx], eax
            //   8b4d10               | mov                 ecx, dword ptr [ebp + 0x10]
            //   8b45f4               | mov                 eax, dword ptr [ebp - 0xc]
            //   894b08               | mov                 dword ptr [ebx + 8], ecx
            //   8b97c4000000         | mov                 edx, dword ptr [edi + 0xc4]
            //   8b4df0               | mov                 ecx, dword ptr [ebp - 0x10]

        $sequence_7 = { 03c0 8945ec 8d441001 2bf0 8945d8 03f3 }
            // n = 6, score = 200
            //   03c0                 | add                 eax, eax
            //   8945ec               | mov                 dword ptr [ebp - 0x14], eax
            //   8d441001             | lea                 eax, [eax + edx + 1]
            //   2bf0                 | sub                 esi, eax
            //   8945d8               | mov                 dword ptr [ebp - 0x28], eax
            //   03f3                 | add                 esi, ebx

        $sequence_8 = { 8b17 894214 8b4508 8b4814 8b17 8b4214 53 }
            // n = 7, score = 200
            //   8b17                 | mov                 edx, dword ptr [edi]
            //   894214               | mov                 dword ptr [edx + 0x14], eax
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   8b4814               | mov                 ecx, dword ptr [eax + 0x14]
            //   8b17                 | mov                 edx, dword ptr [edi]
            //   8b4214               | mov                 eax, dword ptr [edx + 0x14]
            //   53                   | push                ebx

        $sequence_9 = { e8???????? 8b75fc 83c408 8bd8 85f6 7507 8b4f74 }
            // n = 7, score = 200
            //   e8????????           |                     
            //   8b75fc               | mov                 esi, dword ptr [ebp - 4]
            //   83c408               | add                 esp, 8
            //   8bd8                 | mov                 ebx, eax
            //   85f6                 | test                esi, esi
            //   7507                 | jne                 9
            //   8b4f74               | mov                 ecx, dword ptr [edi + 0x74]

    condition:
        7 of them and filesize < 122880
}