rule win_metaencryptor_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.metaencryptor."
        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.metaencryptor"
        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 = { e8???????? 8945fc ebb0 8b5508 52 e8???????? 8b45f4 }
            // n = 7, score = 100
            //   e8????????           |                     
            //   8945fc               | mov                 dword ptr [ebp - 4], eax
            //   ebb0                 | jmp                 0xffffffb2
            //   8b5508               | mov                 edx, dword ptr [ebp + 8]
            //   52                   | push                edx
            //   e8????????           |                     
            //   8b45f4               | mov                 eax, dword ptr [ebp - 0xc]

        $sequence_1 = { 58 43 3030 55 8bec 83ec08 53 }
            // n = 7, score = 100
            //   58                   | pop                 eax
            //   43                   | inc                 ebx
            //   3030                 | xor                 byte ptr [eax], dh
            //   55                   | push                ebp
            //   8bec                 | mov                 ebp, esp
            //   83ec08               | sub                 esp, 8
            //   53                   | push                ebx

        $sequence_2 = { 0fb6cb c1e208 0fb689406a4400 33d1 3355f4 8990f0000000 }
            // n = 6, score = 100
            //   0fb6cb               | movzx               ecx, bl
            //   c1e208               | shl                 edx, 8
            //   0fb689406a4400       | movzx               ecx, byte ptr [ecx + 0x446a40]
            //   33d1                 | xor                 edx, ecx
            //   3355f4               | xor                 edx, dword ptr [ebp - 0xc]
            //   8990f0000000         | mov                 dword ptr [eax + 0xf0], edx

        $sequence_3 = { 330c85d0d44300 330c9550d84300 33f1 8bce }
            // n = 4, score = 100
            //   330c85d0d44300       | xor                 ecx, dword ptr [eax*4 + 0x43d4d0]
            //   330c9550d84300       | xor                 ecx, dword ptr [edx*4 + 0x43d850]
            //   33f1                 | xor                 esi, ecx
            //   8bce                 | mov                 ecx, esi

        $sequence_4 = { 83e13f 83e03f 8b0c8d90d04300 330c8550d74300 8bc2 c1e808 }
            // n = 6, score = 100
            //   83e13f               | and                 ecx, 0x3f
            //   83e03f               | and                 eax, 0x3f
            //   8b0c8d90d04300       | mov                 ecx, dword ptr [ecx*4 + 0x43d090]
            //   330c8550d74300       | xor                 ecx, dword ptr [eax*4 + 0x43d750]
            //   8bc2                 | mov                 eax, edx
            //   c1e808               | shr                 eax, 8

        $sequence_5 = { 85db 7443 8bcf e8???????? 8bc3 5f }
            // n = 6, score = 100
            //   85db                 | test                ebx, ebx
            //   7443                 | je                  0x45
            //   8bcf                 | mov                 ecx, edi
            //   e8????????           |                     
            //   8bc3                 | mov                 eax, ebx
            //   5f                   | pop                 edi

        $sequence_6 = { 50 8d4df0 e8???????? 83c408 85c0 0f85ecfdffff }
            // n = 6, score = 100
            //   50                   | push                eax
            //   8d4df0               | lea                 ecx, [ebp - 0x10]
            //   e8????????           |                     
            //   83c408               | add                 esp, 8
            //   85c0                 | test                eax, eax
            //   0f85ecfdffff         | jne                 0xfffffdf2

        $sequence_7 = { 8b45dc 8b7710 3945f8 740c b89ad0ffff }
            // n = 5, score = 100
            //   8b45dc               | mov                 eax, dword ptr [ebp - 0x24]
            //   8b7710               | mov                 esi, dword ptr [edi + 0x10]
            //   3945f8               | cmp                 dword ptr [ebp - 8], eax
            //   740c                 | je                  0xe
            //   b89ad0ffff           | mov                 eax, 0xffffd09a

        $sequence_8 = { 330c9550d64300 8bd6 33d9 c1ca04 335774 8bca 8bc2 }
            // n = 7, score = 100
            //   330c9550d64300       | xor                 ecx, dword ptr [edx*4 + 0x43d650]
            //   8bd6                 | mov                 edx, esi
            //   33d9                 | xor                 ebx, ecx
            //   c1ca04               | ror                 edx, 4
            //   335774               | xor                 edx, dword ptr [edi + 0x74]
            //   8bca                 | mov                 ecx, edx
            //   8bc2                 | mov                 eax, edx

        $sequence_9 = { 0fb68910494400 33d1 8b4d08 33501c 8b45f0 }
            // n = 5, score = 100
            //   0fb68910494400       | movzx               ecx, byte ptr [ecx + 0x444910]
            //   33d1                 | xor                 edx, ecx
            //   8b4d08               | mov                 ecx, dword ptr [ebp + 8]
            //   33501c               | xor                 edx, dword ptr [eax + 0x1c]
            //   8b45f0               | mov                 eax, dword ptr [ebp - 0x10]

    condition:
        7 of them and filesize < 598016
}