rule win_nozelesn_decryptor_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.nozelesn_decryptor."
        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.nozelesn_decryptor"
        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 = { 8a45a7 85f6 0f8590f9ffff c6459a01 e9???????? 8b459c 8d4dd8 }
            // n = 7, score = 100
            //   8a45a7               | mov                 al, byte ptr [ebp - 0x59]
            //   85f6                 | test                esi, esi
            //   0f8590f9ffff         | jne                 0xfffff996
            //   c6459a01             | mov                 byte ptr [ebp - 0x66], 1
            //   e9????????           |                     
            //   8b459c               | mov                 eax, dword ptr [ebp - 0x64]
            //   8d4dd8               | lea                 ecx, [ebp - 0x28]

        $sequence_1 = { 33f6 e8???????? 84c0 0f85f7000000 807b0400 7507 }
            // n = 6, score = 100
            //   33f6                 | xor                 esi, esi
            //   e8????????           |                     
            //   84c0                 | test                al, al
            //   0f85f7000000         | jne                 0xfd
            //   807b0400             | cmp                 byte ptr [ebx + 4], 0
            //   7507                 | jne                 9

        $sequence_2 = { 50 56 ff15???????? 85c0 750a bfd8600010 e9???????? }
            // n = 7, score = 100
            //   50                   | push                eax
            //   56                   | push                esi
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   750a                 | jne                 0xc
            //   bfd8600010           | mov                 edi, 0x100060d8
            //   e9????????           |                     

        $sequence_3 = { 8939 53 ff15???????? 5f 8bc6 }
            // n = 5, score = 100
            //   8939                 | mov                 dword ptr [ecx], edi
            //   53                   | push                ebx
            //   ff15????????         |                     
            //   5f                   | pop                 edi
            //   8bc6                 | mov                 eax, esi

        $sequence_4 = { 8d45fc 50 8d45f0 50 6a10 5a }
            // n = 6, score = 100
            //   8d45fc               | lea                 eax, [ebp - 4]
            //   50                   | push                eax
            //   8d45f0               | lea                 eax, [ebp - 0x10]
            //   50                   | push                eax
            //   6a10                 | push                0x10
            //   5a                   | pop                 edx

        $sequence_5 = { 7507 c74634d4644600 57 ff7634 e8???????? 59 59 }
            // n = 7, score = 100
            //   7507                 | jne                 9
            //   c74634d4644600       | mov                 dword ptr [esi + 0x34], 0x4664d4
            //   57                   | push                edi
            //   ff7634               | push                dword ptr [esi + 0x34]
            //   e8????????           |                     
            //   59                   | pop                 ecx
            //   59                   | pop                 ecx

        $sequence_6 = { 0f8483010000 3945dc 0f847a010000 e8???????? 6a00 6a00 68f0000000 }
            // n = 7, score = 100
            //   0f8483010000         | je                  0x189
            //   3945dc               | cmp                 dword ptr [ebp - 0x24], eax
            //   0f847a010000         | je                  0x180
            //   e8????????           |                     
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   68f0000000           | push                0xf0

        $sequence_7 = { c1cb05 33de 33cf 33df d1ce 33f1 }
            // n = 6, score = 100
            //   c1cb05               | ror                 ebx, 5
            //   33de                 | xor                 ebx, esi
            //   33cf                 | xor                 ecx, edi
            //   33df                 | xor                 ebx, edi
            //   d1ce                 | ror                 esi, 1
            //   33f1                 | xor                 esi, ecx

        $sequence_8 = { 0f85ad010000 8b06 8b08 8d85e0fdffff 50 }
            // n = 5, score = 100
            //   0f85ad010000         | jne                 0x1b3
            //   8b06                 | mov                 eax, dword ptr [esi]
            //   8b08                 | mov                 ecx, dword ptr [eax]
            //   8d85e0fdffff         | lea                 eax, [ebp - 0x220]
            //   50                   | push                eax

        $sequence_9 = { 660f5425???????? 25ff000000 83c001 25fe010000 f20f591c8510a84600 f20f592c8510a84600 03c0 }
            // n = 7, score = 100
            //   660f5425????????     |                     
            //   25ff000000           | and                 eax, 0xff
            //   83c001               | add                 eax, 1
            //   25fe010000           | and                 eax, 0x1fe
            //   f20f591c8510a84600     | mulsd    xmm3, qword ptr [eax*4 + 0x46a810]
            //   f20f592c8510a84600     | mulsd    xmm5, qword ptr [eax*4 + 0x46a810]
            //   03c0                 | add                 eax, eax

    condition:
        7 of them and filesize < 1122304
}