rule win_chches_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2021-06-10"
        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 = "20210604"
        malpedia_hash = "be09d5d71e77373c0f538068be31a2ad4c69cfbd"
        malpedia_version = "20210616"
        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 = { 57 8bf0 e8???????? 8bf8 81c71d051101 8b07 0598000000 }
            // n = 7, score = 200
            //   57                   | push                edi
            //   8bf0                 | mov                 esi, eax
            //   e8????????           |                     
            //   8bf8                 | mov                 edi, eax
            //   81c71d051101         | add                 edi, 0x111051d
            //   8b07                 | mov                 eax, dword ptr [edi]
            //   0598000000           | add                 eax, 0x98

        $sequence_1 = { 6a08 ffd1 8b5648 50 ffd2 85c0 7403 }
            // n = 7, score = 200
            //   6a08                 | push                8
            //   ffd1                 | call                ecx
            //   8b5648               | mov                 edx, dword ptr [esi + 0x48]
            //   50                   | push                eax
            //   ffd2                 | call                edx
            //   85c0                 | test                eax, eax
            //   7403                 | je                  5

        $sequence_2 = { 8b470c 3bc3 740f 8b96b4010000 8d4de0 51 50 }
            // n = 7, score = 200
            //   8b470c               | mov                 eax, dword ptr [edi + 0xc]
            //   3bc3                 | cmp                 eax, ebx
            //   740f                 | je                  0x11
            //   8b96b4010000         | mov                 edx, dword ptr [esi + 0x1b4]
            //   8d4de0               | lea                 ecx, dword ptr [ebp - 0x20]
            //   51                   | push                ecx
            //   50                   | push                eax

        $sequence_3 = { 8b45f0 50 6a00 6a00 ffd1 8b45bc 894588 }
            // n = 7, score = 200
            //   8b45f0               | mov                 eax, dword ptr [ebp - 0x10]
            //   50                   | push                eax
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   ffd1                 | call                ecx
            //   8b45bc               | mov                 eax, dword ptr [ebp - 0x44]
            //   894588               | mov                 dword ptr [ebp - 0x78], eax

        $sequence_4 = { 7422 50 8b4664 ffd0 8b4b08 8b5114 8b8ea8010000 }
            // n = 7, score = 200
            //   7422                 | je                  0x24
            //   50                   | push                eax
            //   8b4664               | mov                 eax, dword ptr [esi + 0x64]
            //   ffd0                 | call                eax
            //   8b4b08               | mov                 ecx, dword ptr [ebx + 8]
            //   8b5114               | mov                 edx, dword ptr [ecx + 0x14]
            //   8b8ea8010000         | mov                 ecx, dword ptr [esi + 0x1a8]

        $sequence_5 = { 8b4490fc 8b4010 85c0 7469 3901 7461 }
            // n = 6, score = 200
            //   8b4490fc             | mov                 eax, dword ptr [eax + edx*4 - 4]
            //   8b4010               | mov                 eax, dword ptr [eax + 0x10]
            //   85c0                 | test                eax, eax
            //   7469                 | je                  0x6b
            //   3901                 | cmp                 dword ptr [ecx], eax
            //   7461                 | je                  0x63

        $sequence_6 = { 8d4b01 8945fc 394df0 7327 51 85ff 750f }
            // n = 7, score = 200
            //   8d4b01               | lea                 ecx, dword ptr [ebx + 1]
            //   8945fc               | mov                 dword ptr [ebp - 4], eax
            //   394df0               | cmp                 dword ptr [ebp - 0x10], ecx
            //   7327                 | jae                 0x29
            //   51                   | push                ecx
            //   85ff                 | test                edi, edi
            //   750f                 | jne                 0x11

        $sequence_7 = { 85c0 7416 50 8b4644 6a00 ffd0 }
            // n = 6, score = 200
            //   85c0                 | test                eax, eax
            //   7416                 | je                  0x18
            //   50                   | push                eax
            //   8b4644               | mov                 eax, dword ptr [esi + 0x44]
            //   6a00                 | push                0
            //   ffd0                 | call                eax

        $sequence_8 = { 8be5 5d c3 3b448afc 0f845cfaffff 33db }
            // n = 6, score = 200
            //   8be5                 | mov                 esp, ebp
            //   5d                   | pop                 ebp
            //   c3                   | ret                 
            //   3b448afc             | cmp                 eax, dword ptr [edx + ecx*4 - 4]
            //   0f845cfaffff         | je                  0xfffffa62
            //   33db                 | xor                 ebx, ebx

        $sequence_9 = { ffd1 8b17 c7421000000000 8b542414 8b0f }
            // n = 5, score = 200
            //   ffd1                 | call                ecx
            //   8b17                 | mov                 edx, dword ptr [edi]
            //   c7421000000000       | mov                 dword ptr [edx + 0x10], 0
            //   8b542414             | mov                 edx, dword ptr [esp + 0x14]
            //   8b0f                 | mov                 ecx, dword ptr [edi]

    condition:
        7 of them and filesize < 122880
}