rule win_entryshell_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        version = "1"
        description = "Detects win.entryshell."
        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.entryshell"
        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 = { 50 e8???????? 83c414 40 8bf0 6690 }
            // n = 6, score = 100
            //   50                   | push                eax
            //   e8????????           |                     
            //   83c414               | add                 esp, 0x14
            //   40                   | inc                 eax
            //   8bf0                 | mov                 esi, eax
            //   6690                 | nop                 

        $sequence_1 = { 83c404 8d842458410000 50 8d84245c010000 50 57 }
            // n = 6, score = 100
            //   83c404               | add                 esp, 4
            //   8d842458410000       | lea                 eax, [esp + 0x4158]
            //   50                   | push                eax
            //   8d84245c010000       | lea                 eax, [esp + 0x15c]
            //   50                   | push                eax
            //   57                   | push                edi

        $sequence_2 = { 8b74242c 3bc6 7456 8b4c2428 83b90809000000 751d 56 }
            // n = 7, score = 100
            //   8b74242c             | mov                 esi, dword ptr [esp + 0x2c]
            //   3bc6                 | cmp                 eax, esi
            //   7456                 | je                  0x58
            //   8b4c2428             | mov                 ecx, dword ptr [esp + 0x28]
            //   83b90809000000       | cmp                 dword ptr [ecx + 0x908], 0
            //   751d                 | jne                 0x1f
            //   56                   | push                esi

        $sequence_3 = { 83c40c c785f4fbffff4e544c4d c785f8fbffff53535000 c785fcfbffff03000000 83ee01 0f841c020000 83ee01 }
            // n = 7, score = 100
            //   83c40c               | add                 esp, 0xc
            //   c785f4fbffff4e544c4d     | mov    dword ptr [ebp - 0x40c], 0x4d4c544e
            //   c785f8fbffff53535000     | mov    dword ptr [ebp - 0x408], 0x505353
            //   c785fcfbffff03000000     | mov    dword ptr [ebp - 0x404], 3
            //   83ee01               | sub                 esi, 1
            //   0f841c020000         | je                  0x222
            //   83ee01               | sub                 esi, 1

        $sequence_4 = { 8b45fc c745bc01010000 8945d0 8945cc ff15???????? 8d45d4 50 }
            // n = 7, score = 100
            //   8b45fc               | mov                 eax, dword ptr [ebp - 4]
            //   c745bc01010000       | mov                 dword ptr [ebp - 0x44], 0x101
            //   8945d0               | mov                 dword ptr [ebp - 0x30], eax
            //   8945cc               | mov                 dword ptr [ebp - 0x34], eax
            //   ff15????????         |                     
            //   8d45d4               | lea                 eax, [ebp - 0x2c]
            //   50                   | push                eax

        $sequence_5 = { 8d85f8efffff 83c404 50 8b8590efffff 50 51 50 }
            // n = 7, score = 100
            //   8d85f8efffff         | lea                 eax, [ebp - 0x1008]
            //   83c404               | add                 esp, 4
            //   50                   | push                eax
            //   8b8590efffff         | mov                 eax, dword ptr [ebp - 0x1070]
            //   50                   | push                eax
            //   51                   | push                ecx
            //   50                   | push                eax

        $sequence_6 = { 660f13842468080000 ff15???????? 6800080000 8d8424ac200000 6a00 50 e8???????? }
            // n = 7, score = 100
            //   660f13842468080000     | movlpd    qword ptr [esp + 0x868], xmm0
            //   ff15????????         |                     
            //   6800080000           | push                0x800
            //   8d8424ac200000       | lea                 eax, [esp + 0x20ac]
            //   6a00                 | push                0
            //   50                   | push                eax
            //   e8????????           |                     

        $sequence_7 = { 8988444b2501 68???????? e8???????? c9 c3 55 8bec }
            // n = 7, score = 100
            //   8988444b2501         | mov                 dword ptr [eax + 0x1254b44], ecx
            //   68????????           |                     
            //   e8????????           |                     
            //   c9                   | leave               
            //   c3                   | ret                 
            //   55                   | push                ebp
            //   8bec                 | mov                 ebp, esp

        $sequence_8 = { 7e0b 8d4d08 47 03c8 8a140a eb10 83f803 }
            // n = 7, score = 100
            //   7e0b                 | jle                 0xd
            //   8d4d08               | lea                 ecx, [ebp + 8]
            //   47                   | inc                 edi
            //   03c8                 | add                 ecx, eax
            //   8a140a               | mov                 dl, byte ptr [edx + ecx]
            //   eb10                 | jmp                 0x12
            //   83f803               | cmp                 eax, 3

        $sequence_9 = { 757c 8985e0bfffff 6800080000 50 68???????? e8???????? 68???????? }
            // n = 7, score = 100
            //   757c                 | jne                 0x7e
            //   8985e0bfffff         | mov                 dword ptr [ebp - 0x4020], eax
            //   6800080000           | push                0x800
            //   50                   | push                eax
            //   68????????           |                     
            //   e8????????           |                     
            //   68????????           |                     

    condition:
        7 of them and filesize < 663552
}