rule win_crosswalk_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-05-16"
        version = "1"
        description = "Detects win.crosswalk."
        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.crosswalk"
        malpedia_rule_date = "20220513"
        malpedia_hash = "7f4b2229e6ae614d86d74917f6d5b41890e62a26"
        malpedia_version = "20220516"
        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 = { 33f6 8d6e20 8bcd e8???????? }
            // n = 4, score = 1300
            //   33f6                 | movsx               eax, byte ptr [eax]
            //   8d6e20               | dec                 ecx
            //   8bcd                 | inc                 eax
            //   e8????????           |                     

        $sequence_1 = { 458bc6 33d2 488bc8 e8???????? 4533c9 4533c0 }
            // n = 6, score = 1300
            //   458bc6               | add                 edx, eax
            //   33d2                 | imul                eax, edx, 0xe89
            //   488bc8               | inc                 ecx
            //   e8????????           |                     
            //   4533c9               | mov                 eax, eax
            //   4533c0               | imul                ecx

        $sequence_2 = { 4883ec28 4885c9 7402 ffd1 }
            // n = 4, score = 1300
            //   4883ec28             | dec                 ecx
            //   4885c9               | inc                 eax
            //   7402                 | ror                 edx, cl
            //   ffd1                 | inc                 ecx

        $sequence_3 = { 41b88d56e68c 418bc0 f7e9 03d1 c1fa0b 8bc2 }
            // n = 6, score = 1300
            //   41b88d56e68c         | dec                 ecx
            //   418bc0               | inc                 eax
            //   f7e9                 | ror                 edx, cl
            //   03d1                 | add                 edx, eax
            //   c1fa0b               | inc                 ecx
            //   8bc2                 | sub                 edi, 1

        $sequence_4 = { 458d7ee0 418bd7 ff15???????? 4821742420 }
            // n = 4, score = 1300
            //   458d7ee0             | xor                 edx, edx
            //   418bd7               | inc                 ecx
            //   ff15????????         |                     
            //   4821742420           | movsx               eax, byte ptr [eax]

        $sequence_5 = { c1fa0b 8bc2 c1e81f 03d0 69c2890e0000 }
            // n = 5, score = 1300
            //   c1fa0b               | inc                 ecx
            //   8bc2                 | mov                 eax, 0x8ce6568d
            //   c1e81f               | inc                 ecx
            //   03d0                 | mov                 eax, eax
            //   69c2890e0000         | imul                ecx

        $sequence_6 = { ff15???????? 448bf0 4533c9 4533c0 }
            // n = 4, score = 1300
            //   ff15????????         |                     
            //   448bf0               | inc                 esp
            //   4533c9               | mov                 esi, eax
            //   4533c0               | inc                 ebp

        $sequence_7 = { 33d2 410fbe00 49ffc0 d3ca 03d0 4183ef01 }
            // n = 6, score = 1300
            //   33d2                 | xor                 ecx, ecx
            //   410fbe00             | inc                 ebp
            //   49ffc0               | xor                 eax, eax
            //   d3ca                 | xor                 edx, edx
            //   03d0                 | inc                 ecx
            //   4183ef01             | movsx               eax, byte ptr [eax]

        $sequence_8 = { 897de4 8365fc00 8b049d808e4100 8b4de0 }
            // n = 4, score = 200
            //   897de4               | mov                 dword ptr [ebp - 0x1c], edi
            //   8365fc00             | and                 dword ptr [ebp - 4], 0
            //   8b049d808e4100       | mov                 eax, dword ptr [ebx*4 + 0x418e80]
            //   8b4de0               | mov                 ecx, dword ptr [ebp - 0x20]

        $sequence_9 = { 8b0485808e4100 33db 8b7508 57 8b440818 8b4d10 8bf9 }
            // n = 7, score = 200
            //   8b0485808e4100       | mov                 eax, dword ptr [eax*4 + 0x418e80]
            //   33db                 | xor                 ebx, ebx
            //   8b7508               | mov                 esi, dword ptr [ebp + 8]
            //   57                   | push                edi
            //   8b440818             | mov                 eax, dword ptr [eax + ecx + 0x18]
            //   8b4d10               | mov                 ecx, dword ptr [ebp + 0x10]
            //   8bf9                 | mov                 edi, ecx

        $sequence_10 = { 8b45fc 817848f0844100 7409 ff7048 }
            // n = 4, score = 200
            //   8b45fc               | mov                 eax, dword ptr [ebp - 4]
            //   817848f0844100       | cmp                 dword ptr [eax + 0x48], 0x4184f0
            //   7409                 | je                  0xb
            //   ff7048               | push                dword ptr [eax + 0x48]

        $sequence_11 = { 89861c020000 8b45e0 8d4e0c 6a06 8d90fc814100 }
            // n = 5, score = 200
            //   89861c020000         | mov                 dword ptr [esi + 0x21c], eax
            //   8b45e0               | mov                 eax, dword ptr [ebp - 0x20]
            //   8d4e0c               | lea                 ecx, [esi + 0xc]
            //   6a06                 | push                6
            //   8d90fc814100         | lea                 edx, [eax + 0x4181fc]

        $sequence_12 = { 83c404 8bd8 8d45fc 6a00 50 6a0c }
            // n = 6, score = 200
            //   83c404               | add                 esp, 4
            //   8bd8                 | mov                 ebx, eax
            //   8d45fc               | lea                 eax, [ebp - 4]
            //   6a00                 | push                0
            //   50                   | push                eax
            //   6a0c                 | push                0xc

        $sequence_13 = { 8bde 895dd8 8365fc00 8b45e4 8b0485808e4100 8b4de0 f644082801 }
            // n = 7, score = 200
            //   8bde                 | mov                 ebx, esi
            //   895dd8               | mov                 dword ptr [ebp - 0x28], ebx
            //   8365fc00             | and                 dword ptr [ebp - 4], 0
            //   8b45e4               | mov                 eax, dword ptr [ebp - 0x1c]
            //   8b0485808e4100       | mov                 eax, dword ptr [eax*4 + 0x418e80]
            //   8b4de0               | mov                 ecx, dword ptr [ebp - 0x20]
            //   f644082801           | test                byte ptr [eax + ecx + 0x28], 1

        $sequence_14 = { 7810 3de4000000 7309 8b04c5502e4100 5d c3 33c0 }
            // n = 7, score = 200
            //   7810                 | js                  0x12
            //   3de4000000           | cmp                 eax, 0xe4
            //   7309                 | jae                 0xb
            //   8b04c5502e4100       | mov                 eax, dword ptr [eax*8 + 0x412e50]
            //   5d                   | pop                 ebp
            //   c3                   | ret                 
            //   33c0                 | xor                 eax, eax

        $sequence_15 = { eb17 81fa00010000 7313 8a87f4814100 08441619 42 }
            // n = 6, score = 200
            //   eb17                 | jmp                 0x19
            //   81fa00010000         | cmp                 edx, 0x100
            //   7313                 | jae                 0x15
            //   8a87f4814100         | mov                 al, byte ptr [edi + 0x4181f4]
            //   08441619             | or                  byte ptr [esi + edx + 0x19], al
            //   42                   | inc                 edx

    condition:
        7 of them and filesize < 286720
}