rule win_chainshot_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.chainshot."
        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.chainshot"
        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 = { c6041f50 ffc7 81fe00320000 7cc4 b948810000 }
            // n = 5, score = 300
            //   c6041f50             | test                edi, edi
            //   ffc7                 | mov                 esi, 0x80000093
            //   81fe00320000         | jmp                 0xa96
            //   7cc4                 | lea                 eax, [ebp - 4]
            //   b948810000           | mov                 dword ptr [edi], esi

        $sequence_1 = { b901000080 e8???????? 32db e9???????? }
            // n = 4, score = 300
            //   b901000080           | xor                 edx, edx
            //   e8????????           |                     
            //   32db                 | inc                 ecx
            //   e9????????           |                     

        $sequence_2 = { 83e010 83c010 c3 85c9 7906 b804000000 }
            // n = 6, score = 300
            //   83e010               | je                  0xd57
            //   83c010               | and                 dword ptr [edi + 8], 0
            //   c3                   | jmp                 0xd69
            //   85c9                 | dec                 eax
            //   7906                 | mov                 ecx, dword ptr [esp + 0x40]
            //   b804000000           | dec                 eax

        $sequence_3 = { 0f85be000000 c705????????0d000000 e9???????? 83fa06 756c 8d4afd }
            // n = 6, score = 300
            //   0f85be000000         | mov                 ecx, 0x28000000
            //   c705????????0d000000     |     
            //   e9????????           |                     
            //   83fa06               | add                 byte ptr [eax], al
            //   756c                 | or                  al, byte ptr [eax]
            //   8d4afd               | dec                 esp

        $sequence_4 = { 83c010 c3 85c9 7906 }
            // n = 4, score = 300
            //   83c010               | js                  0xdad
            //   c3                   | cmp                 dword ptr [ebp - 4], 0
            //   85c9                 | jne                 0xd6d
            //   7906                 | mov                 esi, 0x800000ac

        $sequence_5 = { b804000000 c3 81e100000040 f7d9 1bc0 f7d8 }
            // n = 6, score = 300
            //   b804000000           | lea                 eax, [edi*4]
            //   c3                   | mov                 edi, ebx
            //   81e100000040         | lea                 ecx, [ecx + 4]
            //   f7d9                 | inc                 edx
            //   1bc0                 | cmp                 dword ptr [ecx], eax
            //   f7d8                 | jne                 0x27d

        $sequence_6 = { 84c0 750a b905050080 e9???????? b907020000 e8???????? eb14 }
            // n = 7, score = 300
            //   84c0                 | cmp                 ebx, 0x400
            //   750a                 | jge                 0x1442
            //   b905050080           | dec                 ebp
            //   e9????????           |                     
            //   b907020000           | mov                 ebp, dword ptr [edi + ebx*8]
            //   e8????????           |                     
            //   eb14                 | dec                 eax

        $sequence_7 = { c3 81e100000040 f7d9 1bc0 83e010 83c010 c3 }
            // n = 7, score = 300
            //   c3                   | dec                 eax
            //   81e100000040         | test                esi, esi
            //   f7d9                 | je                  0x16e5
            //   1bc0                 | dec                 eax
            //   83e010               | lea                 ecx, [esp + 0x30]
            //   83c010               | mov                 ecx, 0x104
            //   c3                   | lea                 eax, [ebp - 0x210]

        $sequence_8 = { b84d5a0000 663b01 740a bbdc000080 e9???????? }
            // n = 5, score = 300
            //   b84d5a0000           | mov                 cl, 1
            //   663b01               | dec                 ebp
            //   740a                 | mov                 eax, dword ptr [eax]
            //   bbdc000080           | mov                 edx, 2
            //   e9????????           |                     

        $sequence_9 = { 33d2 84c0 b900050080 7405 b908020000 }
            // n = 5, score = 300
            //   33d2                 | mov                 dword ptr [esp + eax*2 + 0x168], ebx
            //   84c0                 | and                 eax, 0x3ff
            //   b900050080           | inc                 esp
            //   7405                 | movsx               eax, word ptr [edi + eax*2 + 0xf08]
            //   b908020000           | inc                 ebp

    condition:
        7 of them and filesize < 802816
}