rule win_cur1_downloader_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.cur1_downloader."
        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.cur1_downloader"
        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???????? 3db7000000 750a c744242401000000 eb08 c744242400000000 }
            // n = 6, score = 100
            //   ff15????????         |                     
            //   3db7000000           | mov                 byte ptr [esp + 0x47], 0x35
            //   750a                 | mov                 byte ptr [esp + 0x42], 0x61
            //   c744242401000000     | mov                 byte ptr [esp + 0x43], 0x70
            //   eb08                 | mov                 byte ptr [esp + 0x44], 0x69
            //   c744242400000000     | mov                 byte ptr [esp + 0x45], 0x2e

        $sequence_1 = { 4889442428 488b842490000000 4889442458 488b442458 4889442438 488b442458 4883c008 }
            // n = 7, score = 100
            //   4889442428           | and                 edx, 0x3f
            //   488b842490000000     | dec                 eax
            //   4889442458           | mov                 ecx, edi
            //   488b442458           | dec                 eax
            //   4889442438           | sar                 ecx, 6
            //   488b442458           | dec                 eax
            //   4883c008             | lea                 eax, [0x16104]

        $sequence_2 = { 7419 488b4c2448 e8???????? 488bd0 488b4c2440 e8???????? eb1f }
            // n = 7, score = 100
            //   7419                 | dec                 eax
            //   488b4c2448           | lea                 eax, [0x13a8e]
            //   e8????????           |                     
            //   488bd0               | dec                 eax
            //   488b4c2440           | cmp                 dword ptr [edi - 0x10], eax
            //   e8????????           |                     
            //   eb1f                 | dec                 eax

        $sequence_3 = { 488d0ddf5a0100 e8???????? c705????????02000000 4032ff 8acb e8???????? 4084ff }
            // n = 7, score = 100
            //   488d0ddf5a0100       | lea                 eax, [0x12c61]
            //   e8????????           |                     
            //   c705????????02000000     |     
            //   4032ff               | dec                 eax
            //   8acb                 | lea                 edx, [0x12c62]
            //   e8????????           |                     
            //   4084ff               | inc                 eax

        $sequence_4 = { ff15???????? 90 488d8c2498000000 e8???????? e9???????? 488d8c2498000000 }
            // n = 6, score = 100
            //   ff15????????         |                     
            //   90                   | mov                 byte ptr [esp + 0x1a2], 0x65
            //   488d8c2498000000     | mov                 byte ptr [esp + 0x1a3], 0x61
            //   e8????????           |                     
            //   e9????????           |                     
            //   488d8c2498000000     | mov                 byte ptr [esp + 0x1a4], 0x74

        $sequence_5 = { c68424880100006c c68424890100006c c684248a0100006f c684248b01000063 c684248c01000045 c684248d01000078 c684248e01000000 }
            // n = 7, score = 100
            //   c68424880100006c     | dec                 esp
            //   c68424890100006c     | lea                 ecx, [0xb1c4]
            //   c684248a0100006f     | subsd               xmm1, xmm2
            //   c684248b01000063     | inc                 ecx
            //   c684248c01000045     | mulps               xmm1, xmmword ptr [ecx + eax*8]
            //   c684248d01000078     | movapd              xmm2, xmm1
            //   c684248e01000000     | movapd              xmm0, xmm1

        $sequence_6 = { 41b804010000 488d942400030000 33c9 ff15???????? c744245801000000 e8???????? 833d????????01 }
            // n = 7, score = 100
            //   41b804010000         | mov                 byte ptr [esp + 0x195], 0x65
            //   488d942400030000     | mov                 byte ptr [esp + 0x196], 0x50
            //   33c9                 | mov                 byte ptr [esp + 0x197], 0x72
            //   ff15????????         |                     
            //   c744245801000000     | mov                 byte ptr [esp + 0x198], 0x6f
            //   e8????????           |                     
            //   833d????????01       |                     

        $sequence_7 = { 88442420 48837c242800 7409 0fb6442420 85c0 }
            // n = 5, score = 100
            //   88442420             | test                eax, eax
            //   48837c242800         | dec                 eax
            //   7409                 | lea                 ecx, [0xffffcd04]
            //   0fb6442420           | test                eax, eax
            //   85c0                 | jne                 0x7e6

        $sequence_8 = { 48895108 41f6c101 7427 0fb60a 83e10f 4a0fbe841900e40100 }
            // n = 6, score = 100
            //   48895108             | nop                 
            //   41f6c101             | dec                 eax
            //   7427                 | lea                 eax, [0x21c8a]
            //   0fb60a               | dec                 eax
            //   83e10f               | mov                 dword ptr [esp + 0x28], eax
            //   4a0fbe841900e40100     | movzx    edx, byte ptr [esp + 0x30]

        $sequence_9 = { 488d0de1600100 0f57c0 48890b 488d5308 488d4808 0f1102 }
            // n = 6, score = 100
            //   488d0de1600100       | lea                 edx, [esp + 0x1720]
            //   0f57c0               | xor                 ecx, ecx
            //   48890b               | mov                 dword ptr [esp + 0x68], eax
            //   488d5308             | inc                 ebp
            //   488d4808             | xor                 ecx, ecx
            //   0f1102               | inc                 ebp

    condition:
        7 of them and filesize < 402432
}