rule win_gtpdoor_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        version = "1"
        description = "Detects win.gtpdoor."
        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.gtpdoor"
        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 = { fc b932000000 b800000000 f3aa }
            // n = 4, score = 200
            //   fc                   | cld                 
            //   b932000000           | mov                 ecx, 0x32
            //   b800000000           | mov                 eax, 0
            //   f3aa                 | rep stosb           byte ptr es:[edi], al

        $sequence_1 = { 31d0 8801 8045fb01 8345fc01 }
            // n = 4, score = 200
            //   31d0                 | xor                 eax, edx
            //   8801                 | mov                 byte ptr [ecx], al
            //   8045fb01             | add                 byte ptr [ebp - 5], 1
            //   8345fc01             | add                 dword ptr [ebp - 4], 1

        $sequence_2 = { 750f 837dec00 755a c745f001000000 eb51 }
            // n = 5, score = 100
            //   750f                 | jne                 0x11
            //   837dec00             | cmp                 dword ptr [ebp - 0x14], 0
            //   755a                 | jne                 0x5c
            //   c745f001000000       | mov                 dword ptr [ebp - 0x10], 1
            //   eb51                 | jmp                 0x53

        $sequence_3 = { 488b45f8 48c1e810 480145f8 488b45f8 f7d0 0fb7c0 c9 }
            // n = 7, score = 100
            //   488b45f8             | dec                 eax
            //   48c1e810             | mov                 eax, dword ptr [ebp - 8]
            //   480145f8             | dec                 eax
            //   488b45f8             | shr                 eax, 0x10
            //   f7d0                 | dec                 eax
            //   0fb7c0               | add                 dword ptr [ebp - 8], eax
            //   c9                   | dec                 eax

        $sequence_4 = { 488b7df0 4883c70c be01000000 e8???????? 488b45f0 0fb7400a }
            // n = 6, score = 100
            //   488b7df0             | mov                 eax, 0
            //   4883c70c             | movzx               edi, ax
            //   be01000000           | mov                 edx, eax
            //   e8????????           |                     
            //   488b45f0             | dec                 eax
            //   0fb7400a             | mov                 eax, dword ptr [ebp - 0x10]

        $sequence_5 = { b800000000 fc 8b7dd4 f2ae 89c8 }
            // n = 5, score = 100
            //   b800000000           | mov                 eax, 0
            //   fc                   | cld                 
            //   8b7dd4               | mov                 edi, dword ptr [ebp - 0x2c]
            //   f2ae                 | repne scasb         al, byte ptr es:[edi]
            //   89c8                 | mov                 eax, ecx

        $sequence_6 = { 0fb7f8 e8???????? 89c2 488b45f0 66895001 488b45d8 0fb74004 }
            // n = 7, score = 100
            //   0fb7f8               | dec                 eax
            //   e8????????           |                     
            //   89c2                 | mov                 eax, dword ptr [ebp - 0x20]
            //   488b45f0             | dec                 eax
            //   66895001             | mov                 ecx, 0xffffffff
            //   488b45d8             | dec                 eax
            //   0fb74004             | mov                 dword ptr [ebp - 0x40], eax

        $sequence_7 = { 488b45e0 48c7c1ffffffff 488945c0 b800000000 }
            // n = 4, score = 100
            //   488b45e0             | mov                 eax, dword ptr [ebp - 8]
            //   48c7c1ffffffff       | not                 eax
            //   488945c0             | movzx               eax, ax
            //   b800000000           | leave               

        $sequence_8 = { 48c7c1ffffffff 488985a8f1ffff b800000000 fc }
            // n = 4, score = 100
            //   48c7c1ffffffff       | mov                 word ptr [eax + 1], dx
            //   488985a8f1ffff       | dec                 eax
            //   b800000000           | mov                 eax, dword ptr [ebp - 0x28]
            //   fc                   | movzx               eax, word ptr [eax + 4]

        $sequence_9 = { 8945e8 8b45e8 83c434 5f 5d c3 }
            // n = 6, score = 100
            //   8945e8               | mov                 dword ptr [ebp - 0x18], eax
            //   8b45e8               | mov                 eax, dword ptr [ebp - 0x18]
            //   83c434               | add                 esp, 0x34
            //   5f                   | pop                 edi
            //   5d                   | pop                 ebp
            //   c3                   | ret                 

        $sequence_10 = { 8b45e0 0fb74002 668945e6 8b45e0 0fb710 8b45e0 66895002 }
            // n = 7, score = 100
            //   8b45e0               | mov                 eax, dword ptr [ebp - 0x20]
            //   0fb74002             | movzx               eax, word ptr [eax + 2]
            //   668945e6             | mov                 word ptr [ebp - 0x1a], ax
            //   8b45e0               | mov                 eax, dword ptr [ebp - 0x20]
            //   0fb710               | movzx               edx, word ptr [eax]
            //   8b45e0               | mov                 eax, dword ptr [ebp - 0x20]
            //   66895002             | mov                 word ptr [eax + 2], dx

        $sequence_11 = { e8???????? 66c78580feffff0200 8b4508 8b400c }
            // n = 4, score = 100
            //   e8????????           |                     
            //   66c78580feffff0200     | mov    word ptr [ebp - 0x180], 2
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   8b400c               | mov                 eax, dword ptr [eax + 0xc]

        $sequence_12 = { 8d850afaffff 01d0 8b5514 89c7 89d6 }
            // n = 5, score = 100
            //   8d850afaffff         | lea                 eax, [ebp - 0x5f6]
            //   01d0                 | add                 eax, edx
            //   8b5514               | mov                 edx, dword ptr [ebp + 0x14]
            //   89c7                 | mov                 edi, eax
            //   89d6                 | mov                 esi, edx

        $sequence_13 = { 55 4889e5 4881ec60060000 89bdccf9ffff 4889b5c0f9ffff 48898db0f9ffff 4489c0 }
            // n = 7, score = 100
            //   55                   | dec                 eax
            //   4889e5               | mov                 edi, dword ptr [ebp - 0x10]
            //   4881ec60060000       | dec                 eax
            //   89bdccf9ffff         | add                 edi, 0xc
            //   4889b5c0f9ffff       | mov                 esi, 1
            //   48898db0f9ffff       | dec                 eax
            //   4489c0               | mov                 eax, dword ptr [ebp - 0x10]

    condition:
        7 of them and filesize < 4210688
}