rule win_megacortex_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-07-11"
        version = "1"
        description = "Detects win.megacortex."
        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.megacortex"
        malpedia_rule_date = "20230705"
        malpedia_hash = "42d0574f4405bd7d2b154d321d345acb18834a41"
        malpedia_version = "20230715"
        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 = { f7d9 1bc9 23c1 8d4aff 8945cc 8d45cc }
            // n = 6, score = 400
            //   f7d9                 | neg                 ecx
            //   1bc9                 | sbb                 ecx, ecx
            //   23c1                 | and                 eax, ecx
            //   8d4aff               | lea                 ecx, [edx - 1]
            //   8945cc               | mov                 dword ptr [ebp - 0x34], eax
            //   8d45cc               | lea                 eax, [ebp - 0x34]

        $sequence_1 = { eb69 56 8d8dfcfcffff e8???????? ff460c 8d8d48fcffff 6a01 }
            // n = 7, score = 400
            //   eb69                 | jmp                 0x6b
            //   56                   | push                esi
            //   8d8dfcfcffff         | lea                 ecx, [ebp - 0x304]
            //   e8????????           |                     
            //   ff460c               | inc                 dword ptr [esi + 0xc]
            //   8d8d48fcffff         | lea                 ecx, [ebp - 0x3b8]
            //   6a01                 | push                1

        $sequence_2 = { f7d9 1bc9 23c8 8bc3 03d1 8d5dd4 0355d8 }
            // n = 7, score = 400
            //   f7d9                 | neg                 ecx
            //   1bc9                 | sbb                 ecx, ecx
            //   23c8                 | and                 ecx, eax
            //   8bc3                 | mov                 eax, ebx
            //   03d1                 | add                 edx, ecx
            //   8d5dd4               | lea                 ebx, [ebp - 0x2c]
            //   0355d8               | add                 edx, dword ptr [ebp - 0x28]

        $sequence_3 = { c645fc01 83fa10 722f 8b8dccfdffff 42 8bc1 81fa00100000 }
            // n = 7, score = 400
            //   c645fc01             | mov                 byte ptr [ebp - 4], 1
            //   83fa10               | cmp                 edx, 0x10
            //   722f                 | jb                  0x31
            //   8b8dccfdffff         | mov                 ecx, dword ptr [ebp - 0x234]
            //   42                   | inc                 edx
            //   8bc1                 | mov                 eax, ecx
            //   81fa00100000         | cmp                 edx, 0x1000

        $sequence_4 = { 2bc6 8b16 83e202 f7d9 1bc9 23c8 51 }
            // n = 7, score = 400
            //   2bc6                 | sub                 eax, esi
            //   8b16                 | mov                 edx, dword ptr [esi]
            //   83e202               | and                 edx, 2
            //   f7d9                 | neg                 ecx
            //   1bc9                 | sbb                 ecx, ecx
            //   23c8                 | and                 ecx, eax
            //   51                   | push                ecx

        $sequence_5 = { e8???????? 83c408 85c0 0f8587010000 8b4514 85ff 7454 }
            // n = 7, score = 400
            //   e8????????           |                     
            //   83c408               | add                 esp, 8
            //   85c0                 | test                eax, eax
            //   0f8587010000         | jne                 0x18d
            //   8b4514               | mov                 eax, dword ptr [ebp + 0x14]
            //   85ff                 | test                edi, edi
            //   7454                 | je                  0x56

        $sequence_6 = { e9???????? 6a04 b8???????? e8???????? 33db bfff7f0000 895df0 }
            // n = 7, score = 400
            //   e9????????           |                     
            //   6a04                 | push                4
            //   b8????????           |                     
            //   e8????????           |                     
            //   33db                 | xor                 ebx, ebx
            //   bfff7f0000           | mov                 edi, 0x7fff
            //   895df0               | mov                 dword ptr [ebp - 0x10], ebx

        $sequence_7 = { 894204 83790400 7503 895340 6a08 51 }
            // n = 6, score = 400
            //   894204               | mov                 dword ptr [edx + 4], eax
            //   83790400             | cmp                 dword ptr [ecx + 4], 0
            //   7503                 | jne                 5
            //   895340               | mov                 dword ptr [ebx + 0x40], edx
            //   6a08                 | push                8
            //   51                   | push                ecx

        $sequence_8 = { 8975fc 50 e8???????? 83c40c 5f 5e 5b }
            // n = 7, score = 400
            //   8975fc               | mov                 dword ptr [ebp - 4], esi
            //   50                   | push                eax
            //   e8????????           |                     
            //   83c40c               | add                 esp, 0xc
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi
            //   5b                   | pop                 ebx

        $sequence_9 = { e8???????? 8d45f0 3bf0 0f857affffff 8bc3 8b4df4 64890d00000000 }
            // n = 7, score = 400
            //   e8????????           |                     
            //   8d45f0               | lea                 eax, [ebp - 0x10]
            //   3bf0                 | cmp                 esi, eax
            //   0f857affffff         | jne                 0xffffff80
            //   8bc3                 | mov                 eax, ebx
            //   8b4df4               | mov                 ecx, dword ptr [ebp - 0xc]
            //   64890d00000000       | mov                 dword ptr fs:[0], ecx

    condition:
        7 of them and filesize < 1556480
}