rule win_rapid_ransom_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-04-08"
        version = "1"
        description = "Detects win.rapid_ransom."
        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.rapid_ransom"
        malpedia_rule_date = "20220405"
        malpedia_hash = "ecd38294bd47d5589be5cd5490dc8bb4804afc2a"
        malpedia_version = "20220411"
        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 = { 6801000004 6800a40000 ff75f8 ff15???????? }
            // n = 4, score = 300
            //   6801000004           | push                0x4000001
            //   6800a40000           | push                0xa400
            //   ff75f8               | push                dword ptr [ebp - 8]
            //   ff15????????         |                     

        $sequence_1 = { 8d4001 4e 75f7 ff75fc 51 }
            // n = 5, score = 200
            //   8d4001               | lea                 eax, dword ptr [eax + 1]
            //   4e                   | dec                 esi
            //   75f7                 | jne                 0xfffffff9
            //   ff75fc               | push                dword ptr [ebp - 4]
            //   51                   | push                ecx

        $sequence_2 = { c745f0f5000000 c745e86a000000 e8???????? 68f5000000 57 }
            // n = 5, score = 200
            //   c745f0f5000000       | mov                 dword ptr [ebp - 0x10], 0xf5
            //   c745e86a000000       | mov                 dword ptr [ebp - 0x18], 0x6a
            //   e8????????           |                     
            //   68f5000000           | push                0xf5
            //   57                   | push                edi

        $sequence_3 = { c644241701 57 6a01 e8???????? 83c410 84c0 0f94c0 }
            // n = 7, score = 200
            //   c644241701           | mov                 byte ptr [esp + 0x17], 1
            //   57                   | push                edi
            //   6a01                 | push                1
            //   e8????????           |                     
            //   83c410               | add                 esp, 0x10
            //   84c0                 | test                al, al
            //   0f94c0               | sete                al

        $sequence_4 = { 8bec 51 53 8b5d08 56 8bf2 8975fc }
            // n = 7, score = 200
            //   8bec                 | mov                 ebp, esp
            //   51                   | push                ecx
            //   53                   | push                ebx
            //   8b5d08               | mov                 ebx, dword ptr [ebp + 8]
            //   56                   | push                esi
            //   8bf2                 | mov                 esi, edx
            //   8975fc               | mov                 dword ptr [ebp - 4], esi

        $sequence_5 = { 8b1d???????? 56 57 33ff be???????? ffd3 }
            // n = 6, score = 200
            //   8b1d????????         |                     
            //   56                   | push                esi
            //   57                   | push                edi
            //   33ff                 | xor                 edi, edi
            //   be????????           |                     
            //   ffd3                 | call                ebx

        $sequence_6 = { 8b75fc 5b 56 ff15???????? 50 56 ff15???????? }
            // n = 7, score = 200
            //   8b75fc               | mov                 esi, dword ptr [ebp - 4]
            //   5b                   | pop                 ebx
            //   56                   | push                esi
            //   ff15????????         |                     
            //   50                   | push                eax
            //   56                   | push                esi
            //   ff15????????         |                     

        $sequence_7 = { e8???????? 68f5000000 8d87f5000000 8d8e00010000 50 51 894dec }
            // n = 7, score = 200
            //   e8????????           |                     
            //   68f5000000           | push                0xf5
            //   8d87f5000000         | lea                 eax, dword ptr [edi + 0xf5]
            //   8d8e00010000         | lea                 ecx, dword ptr [esi + 0x100]
            //   50                   | push                eax
            //   51                   | push                ecx
            //   894dec               | mov                 dword ptr [ebp - 0x14], ecx

        $sequence_8 = { 8b4df0 0f1f4000 660f1f840000000000 8bb31c010000 83be7004000000 7412 }
            // n = 6, score = 100
            //   8b4df0               | mov                 ecx, dword ptr [ebp - 0x10]
            //   0f1f4000             | nop                 dword ptr [eax]
            //   660f1f840000000000     | nop    word ptr [eax + eax]
            //   8bb31c010000         | mov                 esi, dword ptr [ebx + 0x11c]
            //   83be7004000000       | cmp                 dword ptr [esi + 0x470], 0
            //   7412                 | je                  0x14

        $sequence_9 = { 0f8497000000 6a00 50 ff75fc }
            // n = 4, score = 100
            //   0f8497000000         | je                  0x9d
            //   6a00                 | push                0
            //   50                   | push                eax
            //   ff75fc               | push                dword ptr [ebp - 4]

        $sequence_10 = { 83e801 79f4 2bf1 46 8d4601 50 e8???????? }
            // n = 7, score = 100
            //   83e801               | sub                 eax, 1
            //   79f4                 | jns                 0xfffffff6
            //   2bf1                 | sub                 esi, ecx
            //   46                   | inc                 esi
            //   8d4601               | lea                 eax, dword ptr [esi + 1]
            //   50                   | push                eax
            //   e8????????           |                     

        $sequence_11 = { 7408 c644240f01 884814 8b780c 85ff }
            // n = 5, score = 100
            //   7408                 | je                  0xa
            //   c644240f01           | mov                 byte ptr [esp + 0xf], 1
            //   884814               | mov                 byte ptr [eax + 0x14], cl
            //   8b780c               | mov                 edi, dword ptr [eax + 0xc]
            //   85ff                 | test                edi, edi

        $sequence_12 = { eb02 33c0 8b3d???????? 6a00 8945b8 }
            // n = 5, score = 100
            //   eb02                 | jmp                 4
            //   33c0                 | xor                 eax, eax
            //   8b3d????????         |                     
            //   6a00                 | push                0
            //   8945b8               | mov                 dword ptr [ebp - 0x48], eax

        $sequence_13 = { 6a02 e8???????? 83c404 8b8674040000 83f8ff 7411 50 }
            // n = 7, score = 100
            //   6a02                 | push                2
            //   e8????????           |                     
            //   83c404               | add                 esp, 4
            //   8b8674040000         | mov                 eax, dword ptr [esi + 0x474]
            //   83f8ff               | cmp                 eax, -1
            //   7411                 | je                  0x13
            //   50                   | push                eax

        $sequence_14 = { 33c0 8945e8 57 33ff }
            // n = 4, score = 100
            //   33c0                 | xor                 eax, eax
            //   8945e8               | mov                 dword ptr [ebp - 0x18], eax
            //   57                   | push                edi
            //   33ff                 | xor                 edi, edi

    condition:
        7 of them and filesize < 286720
}