rule win_fengine_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.fengine."
        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.fengine"
        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 = { ff15???????? ff15???????? 5f 5b 8be5 5d c3 }
            // n = 7, score = 100
            //   ff15????????         |                     
            //   ff15????????         |                     
            //   5f                   | pop                 edi
            //   5b                   | pop                 ebx
            //   8be5                 | mov                 esp, ebp
            //   5d                   | pop                 ebp
            //   c3                   | ret                 

        $sequence_1 = { 8b5e24 c1e003 50 03fa 03da e8???????? 8bc8 }
            // n = 7, score = 100
            //   8b5e24               | mov                 ebx, dword ptr [esi + 0x24]
            //   c1e003               | shl                 eax, 3
            //   50                   | push                eax
            //   03fa                 | add                 edi, edx
            //   03da                 | add                 ebx, edx
            //   e8????????           |                     
            //   8bc8                 | mov                 ecx, eax

        $sequence_2 = { 57 8d8decefffff 51 50 8d85fcf7ffff 50 }
            // n = 6, score = 100
            //   57                   | push                edi
            //   8d8decefffff         | lea                 ecx, [ebp - 0x1014]
            //   51                   | push                ecx
            //   50                   | push                eax
            //   8d85fcf7ffff         | lea                 eax, [ebp - 0x804]
            //   50                   | push                eax

        $sequence_3 = { e8???????? 85c0 742e 8bcf e8???????? 8b07 8b4028 }
            // n = 7, score = 100
            //   e8????????           |                     
            //   85c0                 | test                eax, eax
            //   742e                 | je                  0x30
            //   8bcf                 | mov                 ecx, edi
            //   e8????????           |                     
            //   8b07                 | mov                 eax, dword ptr [edi]
            //   8b4028               | mov                 eax, dword ptr [eax + 0x28]

        $sequence_4 = { 8d8424f9000000 68ff070000 6a00 50 c684240401000000 }
            // n = 5, score = 100
            //   8d8424f9000000       | lea                 eax, [esp + 0xf9]
            //   68ff070000           | push                0x7ff
            //   6a00                 | push                0
            //   50                   | push                eax
            //   c684240401000000     | mov                 byte ptr [esp + 0x104], 0

        $sequence_5 = { 33c5 8945fc b9???????? c785f8efffff00000000 e8???????? }
            // n = 5, score = 100
            //   33c5                 | xor                 eax, ebp
            //   8945fc               | mov                 dword ptr [ebp - 4], eax
            //   b9????????           |                     
            //   c785f8efffff00000000     | mov    dword ptr [ebp - 0x1008], 0
            //   e8????????           |                     

        $sequence_6 = { 731b 6a0d ff15???????? 5f 5e 33c0 5b }
            // n = 7, score = 100
            //   731b                 | jae                 0x1d
            //   6a0d                 | push                0xd
            //   ff15????????         |                     
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi
            //   33c0                 | xor                 eax, eax
            //   5b                   | pop                 ebx

        $sequence_7 = { 894f08 8bd6 891481 ff470c }
            // n = 4, score = 100
            //   894f08               | mov                 dword ptr [edi + 8], ecx
            //   8bd6                 | mov                 edx, esi
            //   891481               | mov                 dword ptr [ecx + eax*4], edx
            //   ff470c               | inc                 dword ptr [edi + 0xc]

        $sequence_8 = { 81ec04080000 a1???????? 33c5 8945fc 6800040000 8d85fcfbffff 50 }
            // n = 7, score = 100
            //   81ec04080000         | sub                 esp, 0x804
            //   a1????????           |                     
            //   33c5                 | xor                 eax, ebp
            //   8945fc               | mov                 dword ptr [ebp - 4], eax
            //   6800040000           | push                0x400
            //   8d85fcfbffff         | lea                 eax, [ebp - 0x404]
            //   50                   | push                eax

        $sequence_9 = { 5d c3 8b4a3c 8d81f8000000 3bd8 72b0 }
            // n = 6, score = 100
            //   5d                   | pop                 ebp
            //   c3                   | ret                 
            //   8b4a3c               | mov                 ecx, dword ptr [edx + 0x3c]
            //   8d81f8000000         | lea                 eax, [ecx + 0xf8]
            //   3bd8                 | cmp                 ebx, eax
            //   72b0                 | jb                  0xffffffb2

    condition:
        7 of them and filesize < 210944
}