rule win_downdelph_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-05-04"
        version = "1"
        description = "Detects win.downdelph."
        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.downdelph"
        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 = { ba02000000 e8???????? 8d45f0 8b15???????? e8???????? 8d45f4 ba03000000 }
            // n = 7, score = 100
            //   ba02000000           | mov                 edx, 2
            //   e8????????           |                     
            //   8d45f0               | lea                 eax, [ebp - 0x10]
            //   8b15????????         |                     
            //   e8????????           |                     
            //   8d45f4               | lea                 eax, [ebp - 0xc]
            //   ba03000000           | mov                 edx, 3

        $sequence_1 = { 49 ba01000000 8b45f8 e8???????? 8b55c8 }
            // n = 5, score = 100
            //   49                   | dec                 ecx
            //   ba01000000           | mov                 edx, 1
            //   8b45f8               | mov                 eax, dword ptr [ebp - 8]
            //   e8????????           |                     
            //   8b55c8               | mov                 edx, dword ptr [ebp - 0x38]

        $sequence_2 = { 7405 83ef04 8b3f 56 8d45d8 }
            // n = 5, score = 100
            //   7405                 | je                  7
            //   83ef04               | sub                 edi, 4
            //   8b3f                 | mov                 edi, dword ptr [edi]
            //   56                   | push                esi
            //   8d45d8               | lea                 eax, [ebp - 0x28]

        $sequence_3 = { 6a00 6a00 e8???????? a3???????? 833d????????00 7402 b301 }
            // n = 7, score = 100
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   e8????????           |                     
            //   a3????????           |                     
            //   833d????????00       |                     
            //   7402                 | je                  4
            //   b301                 | mov                 bl, 1

        $sequence_4 = { 0345e8 33c9 e8???????? 837df401 7e7f 83450804 ff4df4 }
            // n = 7, score = 100
            //   0345e8               | add                 eax, dword ptr [ebp - 0x18]
            //   33c9                 | xor                 ecx, ecx
            //   e8????????           |                     
            //   837df401             | cmp                 dword ptr [ebp - 0xc], 1
            //   7e7f                 | jle                 0x81
            //   83450804             | add                 dword ptr [ebp + 8], 4
            //   ff4df4               | dec                 dword ptr [ebp - 0xc]

        $sequence_5 = { 8b55cc 8d45f8 e8???????? 837df800 750d }
            // n = 5, score = 100
            //   8b55cc               | mov                 edx, dword ptr [ebp - 0x34]
            //   8d45f8               | lea                 eax, [ebp - 8]
            //   e8????????           |                     
            //   837df800             | cmp                 dword ptr [ebp - 8], 0
            //   750d                 | jne                 0xf

        $sequence_6 = { 837de800 740a 836de808 8b45e8 8b7804 8b45f8 }
            // n = 6, score = 100
            //   837de800             | cmp                 dword ptr [ebp - 0x18], 0
            //   740a                 | je                  0xc
            //   836de808             | sub                 dword ptr [ebp - 0x18], 8
            //   8b45e8               | mov                 eax, dword ptr [ebp - 0x18]
            //   8b7804               | mov                 edi, dword ptr [eax + 4]
            //   8b45f8               | mov                 eax, dword ptr [ebp - 8]

        $sequence_7 = { 8945f0 33c0 43 81e3ff000080 7908 4b }
            // n = 6, score = 100
            //   8945f0               | mov                 dword ptr [ebp - 0x10], eax
            //   33c0                 | xor                 eax, eax
            //   43                   | inc                 ebx
            //   81e3ff000080         | and                 ebx, 0x800000ff
            //   7908                 | jns                 0xa
            //   4b                   | dec                 ebx

        $sequence_8 = { 4e 75d6 8b45dc 89470c }
            // n = 4, score = 100
            //   4e                   | dec                 esi
            //   75d6                 | jne                 0xffffffd8
            //   8b45dc               | mov                 eax, dword ptr [ebp - 0x24]
            //   89470c               | mov                 dword ptr [edi + 0xc], eax

        $sequence_9 = { 8d45f8 33c9 ba06000000 e8???????? }
            // n = 4, score = 100
            //   8d45f8               | lea                 eax, [ebp - 8]
            //   33c9                 | xor                 ecx, ecx
            //   ba06000000           | mov                 edx, 6
            //   e8????????           |                     

    condition:
        7 of them and filesize < 172032
}