rule win_teslacrypt_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2020-12-22"
        version = "1"
        description = "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.teslacrypt"
        malpedia_rule_date = "20201222"
        malpedia_hash = "30354d830a29f0fbd3714d93d94dea941d77a130"
        malpedia_version = "20201023"
        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 = { 334514 894534 334518 894538 }
            // n = 4, score = 900
            //   334514               | xor                 eax, dword ptr [ebp + 0x14]
            //   894534               | mov                 dword ptr [ebp + 0x34], eax
            //   334518               | xor                 eax, dword ptr [ebp + 0x18]
            //   894538               | mov                 dword ptr [ebp + 0x38], eax

        $sequence_1 = { 894d48 31ca 89554c 89d0 51 }
            // n = 5, score = 900
            //   894d48               | mov                 dword ptr [ebp + 0x48], ecx
            //   31ca                 | xor                 edx, ecx
            //   89554c               | mov                 dword ptr [ebp + 0x4c], edx
            //   89d0                 | mov                 eax, edx
            //   51                   | push                ecx

        $sequence_2 = { 5f 5e 5b 5d 31c0 c3 55 }
            // n = 7, score = 900
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi
            //   5b                   | pop                 ebx
            //   5d                   | pop                 ebp
            //   31c0                 | xor                 eax, eax
            //   c3                   | ret                 
            //   55                   | push                ebp

        $sequence_3 = { 89c6 5a 59 83f608 }
            // n = 4, score = 900
            //   89c6                 | mov                 esi, eax
            //   5a                   | pop                 edx
            //   59                   | pop                 ecx
            //   83f608               | xor                 esi, 8

        $sequence_4 = { 31ca 89d0 5a 59 894550 334534 894554 }
            // n = 7, score = 900
            //   31ca                 | xor                 edx, ecx
            //   89d0                 | mov                 eax, edx
            //   5a                   | pop                 edx
            //   59                   | pop                 ecx
            //   894550               | mov                 dword ptr [ebp + 0x50], eax
            //   334534               | xor                 eax, dword ptr [ebp + 0x34]
            //   894554               | mov                 dword ptr [ebp + 0x54], eax

        $sequence_5 = { 31f9 894d28 31ca 89552c }
            // n = 4, score = 900
            //   31f9                 | xor                 ecx, edi
            //   894d28               | mov                 dword ptr [ebp + 0x28], ecx
            //   31ca                 | xor                 edx, ecx
            //   89552c               | mov                 dword ptr [ebp + 0x2c], edx

        $sequence_6 = { 5d 334500 335d04 8b6c2418 }
            // n = 4, score = 900
            //   5d                   | pop                 ebp
            //   334500               | xor                 eax, dword ptr [ebp]
            //   335d04               | xor                 ebx, dword ptr [ebp + 4]
            //   8b6c2418             | mov                 ebp, dword ptr [esp + 0x18]

        $sequence_7 = { 334d08 33550c 81ffa0000000 0f8452030000 }
            // n = 4, score = 900
            //   334d08               | xor                 ecx, dword ptr [ebp + 8]
            //   33550c               | xor                 edx, dword ptr [ebp + 0xc]
            //   81ffa0000000         | cmp                 edi, 0xa0
            //   0f8452030000         | je                  0x358

        $sequence_8 = { 83c138 894c2420 8944241c 8b44241c 6bc828 8b542428 01ca }
            // n = 7, score = 100
            //   83c138               | add                 ecx, 0x38
            //   894c2420             | mov                 dword ptr [esp + 0x20], ecx
            //   8944241c             | mov                 dword ptr [esp + 0x1c], eax
            //   8b44241c             | mov                 eax, dword ptr [esp + 0x1c]
            //   6bc828               | imul                ecx, eax, 0x28
            //   8b542428             | mov                 edx, dword ptr [esp + 0x28]
            //   01ca                 | add                 edx, ecx

        $sequence_9 = { 8b91a4000000 83fa00 89542464 89442468 0f84d3010000 }
            // n = 5, score = 100
            //   8b91a4000000         | mov                 edx, dword ptr [ecx + 0xa4]
            //   83fa00               | cmp                 edx, 0
            //   89542464             | mov                 dword ptr [esp + 0x64], edx
            //   89442468             | mov                 dword ptr [esp + 0x68], eax
            //   0f84d3010000         | je                  0x1d9

        $sequence_10 = { 83b88400000000 8944245c 894c2458 0f84e1010000 b801000000 8b4c245c }
            // n = 6, score = 100
            //   83b88400000000       | cmp                 dword ptr [eax + 0x84], 0
            //   8944245c             | mov                 dword ptr [esp + 0x5c], eax
            //   894c2458             | mov                 dword ptr [esp + 0x58], ecx
            //   0f84e1010000         | je                  0x1e7
            //   b801000000           | mov                 eax, 1
            //   8b4c245c             | mov                 ecx, dword ptr [esp + 0x5c]

        $sequence_11 = { 8b5128 8b74244c 01d6 8b3d???????? 8b7f20 89e3 }
            // n = 6, score = 100
            //   8b5128               | mov                 edx, dword ptr [ecx + 0x28]
            //   8b74244c             | mov                 esi, dword ptr [esp + 0x4c]
            //   01d6                 | add                 esi, edx
            //   8b3d????????         |                     
            //   8b7f20               | mov                 edi, dword ptr [edi + 0x20]
            //   89e3                 | mov                 ebx, esp

        $sequence_12 = { 8b4c241c 83c101 8b542414 83c228 8b74246c 39f1 89442410 }
            // n = 7, score = 100
            //   8b4c241c             | mov                 ecx, dword ptr [esp + 0x1c]
            //   83c101               | add                 ecx, 1
            //   8b542414             | mov                 edx, dword ptr [esp + 0x14]
            //   83c228               | add                 edx, 0x28
            //   8b74246c             | mov                 esi, dword ptr [esp + 0x6c]
            //   39f1                 | cmp                 ecx, esi
            //   89442410             | mov                 dword ptr [esp + 0x10], eax

        $sequence_13 = { 890424 e8???????? b8ffffffff 89442424 e9???????? 8b442430 890424 }
            // n = 7, score = 100
            //   890424               | mov                 dword ptr [esp], eax
            //   e8????????           |                     
            //   b8ffffffff           | mov                 eax, 0xffffffff
            //   89442424             | mov                 dword ptr [esp + 0x24], eax
            //   e9????????           |                     
            //   8b442430             | mov                 eax, dword ptr [esp + 0x30]
            //   890424               | mov                 dword ptr [esp], eax

        $sequence_14 = { 89b42484000000 8b7274 89b42488000000 8b7268 89b4248c000000 8b7264 89b42490000000 }
            // n = 7, score = 100
            //   89b42484000000       | mov                 dword ptr [esp + 0x84], esi
            //   8b7274               | mov                 esi, dword ptr [edx + 0x74]
            //   89b42488000000       | mov                 dword ptr [esp + 0x88], esi
            //   8b7268               | mov                 esi, dword ptr [edx + 0x68]
            //   89b4248c000000       | mov                 dword ptr [esp + 0x8c], esi
            //   8b7264               | mov                 esi, dword ptr [edx + 0x64]
            //   89b42490000000       | mov                 dword ptr [esp + 0x90], esi

        $sequence_15 = { 890424 89442430 894c242c e8???????? 89c1 }
            // n = 5, score = 100
            //   890424               | mov                 dword ptr [esp], eax
            //   89442430             | mov                 dword ptr [esp + 0x30], eax
            //   894c242c             | mov                 dword ptr [esp + 0x2c], ecx
            //   e8????????           |                     
            //   89c1                 | mov                 ecx, eax

    condition:
        7 of them and filesize < 1187840
}