rule win_rapid_ransom_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2020-10-14"
        version = "1"
        description = "autogenerated rule brought to you by yara-signator"
        tool = "yara-signator v0.5.0"
        tool_config = "callsandjumps;datarefs;binvalue"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.rapid_ransom"
        malpedia_rule_date = "20201014"
        malpedia_hash = "a7e3bd57eaf12bf3ea29a863c041091ba3af9ac9"
        malpedia_version = "20201014"
        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 = { 50 6801000004 6800a40000 ff75f8 }
            // n = 4, score = 300
            //   50                   | push                eax
            //   6801000004           | push                0x4000001
            //   6800a40000           | push                0xa400
            //   ff75f8               | push                dword ptr [ebp - 8]

        $sequence_1 = { 6a00 ff75f0 ff75f8 ff15???????? }
            // n = 4, score = 200
            //   6a00                 | push                0
            //   ff75f0               | push                dword ptr [ebp - 0x10]
            //   ff75f8               | push                dword ptr [ebp - 8]
            //   ff15????????         |                     

        $sequence_2 = { 8b4d08 ba???????? 68???????? 6a00 }
            // n = 4, score = 200
            //   8b4d08               | mov                 ecx, dword ptr [ebp + 8]
            //   ba????????           |                     
            //   68????????           |                     
            //   6a00                 | push                0

        $sequence_3 = { 8d4601 5e c3 33c0 }
            // n = 4, score = 200
            //   8d4601               | lea                 eax, [esi + 1]
            //   5e                   | pop                 esi
            //   c3                   | ret                 
            //   33c0                 | xor                 eax, eax

        $sequence_4 = { 6a07 6a00 ff75fc ffd7 85c0 }
            // n = 5, score = 200
            //   6a07                 | push                7
            //   6a00                 | push                0
            //   ff75fc               | push                dword ptr [ebp - 4]
            //   ffd7                 | call                edi
            //   85c0                 | test                eax, eax

        $sequence_5 = { 56 ff15???????? 8a44240e 84c0 751d }
            // n = 5, score = 200
            //   56                   | push                esi
            //   ff15????????         |                     
            //   8a44240e             | mov                 al, byte ptr [esp + 0xe]
            //   84c0                 | test                al, al
            //   751d                 | jne                 0x1f

        $sequence_6 = { 5b 56 ff15???????? 50 56 }
            // n = 5, score = 200
            //   5b                   | pop                 ebx
            //   56                   | push                esi
            //   ff15????????         |                     
            //   50                   | push                eax
            //   56                   | push                esi

        $sequence_7 = { 8906 85c0 743b 8b0f 41 }
            // n = 5, score = 200
            //   8906                 | mov                 dword ptr [esi], eax
            //   85c0                 | test                eax, eax
            //   743b                 | je                  0x3d
            //   8b0f                 | mov                 ecx, dword ptr [edi]
            //   41                   | inc                 ecx

        $sequence_8 = { 6801000040 ff750c 53 ff15???????? }
            // n = 4, score = 200
            //   6801000040           | push                0x40000001
            //   ff750c               | push                dword ptr [ebp + 0xc]
            //   53                   | push                ebx
            //   ff15????????         |                     

        $sequence_9 = { 81fe00020000 72dd b001 5e c3 ff15???????? 85c0 }
            // n = 7, score = 100
            //   81fe00020000         | cmp                 esi, 0x200
            //   72dd                 | jb                  0xffffffdf
            //   b001                 | mov                 al, 1
            //   5e                   | pop                 esi
            //   c3                   | ret                 
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax

        $sequence_10 = { 50 51 8d45a8 50 56 ff15???????? }
            // n = 6, score = 100
            //   50                   | push                eax
            //   51                   | push                ecx
            //   8d45a8               | lea                 eax, [ebp - 0x58]
            //   50                   | push                eax
            //   56                   | push                esi
            //   ff15????????         |                     

        $sequence_11 = { 57 a3???????? e8???????? 68???????? e8???????? 8b35???????? 83c408 }
            // n = 7, score = 100
            //   57                   | push                edi
            //   a3????????           |                     
            //   e8????????           |                     
            //   68????????           |                     
            //   e8????????           |                     
            //   8b35????????         |                     
            //   83c408               | add                 esp, 8

        $sequence_12 = { b9???????? ebce 68???????? 6a00 6801001f00 }
            // n = 5, score = 100
            //   b9????????           |                     
            //   ebce                 | jmp                 0xffffffd0
            //   68????????           |                     
            //   6a00                 | push                0
            //   6801001f00           | push                0x1f0001

        $sequence_13 = { c1ff06 6bd838 8b04bde8d04100 f644032801 7444 }
            // n = 5, score = 100
            //   c1ff06               | sar                 edi, 6
            //   6bd838               | imul                ebx, eax, 0x38
            //   8b04bde8d04100       | mov                 eax, dword ptr [edi*4 + 0x41d0e8]
            //   f644032801           | test                byte ptr [ebx + eax + 0x28], 1
            //   7444                 | je                  0x46

        $sequence_14 = { 8365c800 c745cc8f4f4000 a1???????? 8d4dc8 33c1 8945d0 }
            // n = 6, score = 100
            //   8365c800             | and                 dword ptr [ebp - 0x38], 0
            //   c745cc8f4f4000       | mov                 dword ptr [ebp - 0x34], 0x404f8f
            //   a1????????           |                     
            //   8d4dc8               | lea                 ecx, [ebp - 0x38]
            //   33c1                 | xor                 eax, ecx
            //   8945d0               | mov                 dword ptr [ebp - 0x30], eax

    condition:
        7 of them and filesize < 286720
}