rule win_cryptowall_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.cryptowall"
        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 = { 6a00 6a40 6a01 6a01 6a00 6a00 8d55e8 }
            // n = 7, score = 2100
            //   6a00                 | push                0
            //   6a40                 | push                0x40
            //   6a01                 | push                1
            //   6a01                 | push                1
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   8d55e8               | lea                 edx, [ebp - 0x18]

        $sequence_1 = { e8???????? 83c408 8b0d???????? 894104 }
            // n = 4, score = 2100
            //   e8????????           |                     
            //   83c408               | add                 esp, 8
            //   8b0d????????         |                     
            //   894104               | mov                 dword ptr [ecx + 4], eax

        $sequence_2 = { 99 b91a000000 f7f9 83c261 8b45f4 }
            // n = 5, score = 2100
            //   99                   | cdq                 
            //   b91a000000           | mov                 ecx, 0x1a
            //   f7f9                 | idiv                ecx
            //   83c261               | add                 edx, 0x61
            //   8b45f4               | mov                 eax, dword ptr [ebp - 0xc]

        $sequence_3 = { 837d0800 7502 eb4f 6a08 6a00 }
            // n = 5, score = 2100
            //   837d0800             | cmp                 dword ptr [ebp + 8], 0
            //   7502                 | jne                 4
            //   eb4f                 | jmp                 0x51
            //   6a08                 | push                8
            //   6a00                 | push                0

        $sequence_4 = { 8b5018 52 e8???????? 8b4028 }
            // n = 4, score = 2100
            //   8b5018               | mov                 edx, dword ptr [eax + 0x18]
            //   52                   | push                edx
            //   e8????????           |                     
            //   8b4028               | mov                 eax, dword ptr [eax + 0x28]

        $sequence_5 = { 8945fc 8b4dfc 0fb711 81fa4d5a0000 740d }
            // n = 5, score = 2100
            //   8945fc               | mov                 dword ptr [ebp - 4], eax
            //   8b4dfc               | mov                 ecx, dword ptr [ebp - 4]
            //   0fb711               | movzx               edx, word ptr [ecx]
            //   81fa4d5a0000         | cmp                 edx, 0x5a4d
            //   740d                 | je                  0xf

        $sequence_6 = { 894834 5d c3 55 8bec 83ec0c c745fc00000000 }
            // n = 7, score = 2100
            //   894834               | mov                 dword ptr [eax + 0x34], ecx
            //   5d                   | pop                 ebp
            //   c3                   | ret                 
            //   55                   | push                ebp
            //   8bec                 | mov                 ebp, esp
            //   83ec0c               | sub                 esp, 0xc
            //   c745fc00000000       | mov                 dword ptr [ebp - 4], 0

        $sequence_7 = { 6a00 6a00 6a40 6a01 6a01 6880000000 6a00 }
            // n = 7, score = 2100
            //   6a00                 | push                0
            //   6a00                 | push                0
            //   6a40                 | push                0x40
            //   6a01                 | push                1
            //   6a01                 | push                1
            //   6880000000           | push                0x80
            //   6a00                 | push                0

        $sequence_8 = { 68a5470b2b 6a01 6a00 e8???????? 83c40c 8b15???????? }
            // n = 6, score = 2100
            //   68a5470b2b           | push                0x2b0b47a5
            //   6a01                 | push                1
            //   6a00                 | push                0
            //   e8????????           |                     
            //   83c40c               | add                 esp, 0xc
            //   8b15????????         |                     

        $sequence_9 = { 8d4df4 51 8d55dc 52 8b450c }
            // n = 5, score = 2100
            //   8d4df4               | lea                 ecx, [ebp - 0xc]
            //   51                   | push                ecx
            //   8d55dc               | lea                 edx, [ebp - 0x24]
            //   52                   | push                edx
            //   8b450c               | mov                 eax, dword ptr [ebp + 0xc]

    condition:
        7 of them and filesize < 417792
}