rule win_teslacrypt_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-04-08"
        version = "1"
        description = "Detects win.teslacrypt."
        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.teslacrypt"
        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 = { 334500 335d04 334d08 33550c 81ffa0000000 0f8452030000 }
            // n = 6, score = 900
            //   334500               | xor                 eax, dword ptr [ebp]
            //   335d04               | xor                 ebx, dword ptr [ebp + 4]
            //   334d08               | xor                 ecx, dword ptr [ebp + 8]
            //   33550c               | xor                 edx, dword ptr [ebp + 0xc]
            //   81ffa0000000         | cmp                 edi, 0xa0
            //   0f8452030000         | je                  0x358

        $sequence_1 = { 334500 335d04 8b6c2418 894500 895d04 }
            // n = 5, score = 900
            //   334500               | xor                 eax, dword ptr [ebp]
            //   335d04               | xor                 ebx, dword ptr [ebp + 4]
            //   8b6c2418             | mov                 ebp, dword ptr [esp + 0x18]
            //   894500               | mov                 dword ptr [ebp], eax
            //   895d04               | mov                 dword ptr [ebp + 4], ebx

        $sequence_2 = { 56 57 8b742414 8b06 8b5e04 8b4e08 }
            // n = 6, score = 900
            //   56                   | push                esi
            //   57                   | push                edi
            //   8b742414             | mov                 esi, dword ptr [esp + 0x14]
            //   8b06                 | mov                 eax, dword ptr [esi]
            //   8b5e04               | mov                 ebx, dword ptr [esi + 4]
            //   8b4e08               | mov                 ecx, dword ptr [esi + 8]

        $sequence_3 = { 335d04 8b542418 8902 895a04 897208 897a0c 31c0 }
            // n = 7, score = 900
            //   335d04               | xor                 ebx, dword ptr [ebp + 4]
            //   8b542418             | mov                 edx, dword ptr [esp + 0x18]
            //   8902                 | mov                 dword ptr [edx], eax
            //   895a04               | mov                 dword ptr [edx + 4], ebx
            //   897208               | mov                 dword ptr [edx + 8], esi
            //   897a0c               | mov                 dword ptr [edx + 0xc], edi
            //   31c0                 | xor                 eax, eax

        $sequence_4 = { 0f8456030000 81ffc0000000 0f84ae010000 81ffe0000000 740a b8ffffffff }
            // n = 6, score = 900
            //   0f8456030000         | je                  0x35c
            //   81ffc0000000         | cmp                 edi, 0xc0
            //   0f84ae010000         | je                  0x1b4
            //   81ffe0000000         | cmp                 edi, 0xe0
            //   740a                 | je                  0xc
            //   b8ffffffff           | mov                 eax, 0xffffffff

        $sequence_5 = { 334500 335d04 83c510 8b7508 8b7d0c 55 c1c310 }
            // n = 7, score = 900
            //   334500               | xor                 eax, dword ptr [ebp]
            //   335d04               | xor                 ebx, dword ptr [ebp + 4]
            //   83c510               | add                 ebp, 0x10
            //   8b7508               | mov                 esi, dword ptr [ebp + 8]
            //   8b7d0c               | mov                 edi, dword ptr [ebp + 0xc]
            //   55                   | push                ebp
            //   c1c310               | rol                 ebx, 0x10

        $sequence_6 = { 31ca 89d0 5a 59 8985b0000000 338594000000 }
            // n = 6, score = 900
            //   31ca                 | xor                 edx, ecx
            //   89d0                 | mov                 eax, edx
            //   5a                   | pop                 edx
            //   59                   | pop                 ecx
            //   8985b0000000         | mov                 dword ptr [ebp + 0xb0], eax
            //   338594000000         | xor                 eax, dword ptr [ebp + 0x94]

        $sequence_7 = { 31ca 89d0 89c6 5a 59 83f604 897540 }
            // n = 7, score = 900
            //   31ca                 | xor                 edx, ecx
            //   89d0                 | mov                 eax, edx
            //   89c6                 | mov                 esi, eax
            //   5a                   | pop                 edx
            //   59                   | pop                 ecx
            //   83f604               | xor                 esi, 4
            //   897540               | mov                 dword ptr [ebp + 0x40], esi

        $sequence_8 = { 897308 897b04 8b74244c 8933 89442444 ffd1 }
            // n = 6, score = 100
            //   897308               | mov                 dword ptr [ebx + 8], esi
            //   897b04               | mov                 dword ptr [ebx + 4], edi
            //   8b74244c             | mov                 esi, dword ptr [esp + 0x4c]
            //   8933                 | mov                 dword ptr [ebx], esi
            //   89442444             | mov                 dword ptr [esp + 0x44], eax
            //   ffd1                 | call                ecx

        $sequence_9 = { 89442414 ffd1 83ec10 89442410 83c454 }
            // n = 5, score = 100
            //   89442414             | mov                 dword ptr [esp + 0x14], eax
            //   ffd1                 | call                ecx
            //   83ec10               | sub                 esp, 0x10
            //   89442410             | mov                 dword ptr [esp + 0x10], eax
            //   83c454               | add                 esp, 0x54

        $sequence_10 = { 83c214 8b4014 39d0 8944242c 89542428 }
            // n = 5, score = 100
            //   83c214               | add                 edx, 0x14
            //   8b4014               | mov                 eax, dword ptr [eax + 0x14]
            //   39d0                 | cmp                 eax, edx
            //   8944242c             | mov                 dword ptr [esp + 0x2c], eax
            //   89542428             | mov                 dword ptr [esp + 0x28], edx

        $sequence_11 = { 8944243c 894c2438 ffd2 83ec04 31c9 }
            // n = 5, score = 100
            //   8944243c             | mov                 dword ptr [esp + 0x3c], eax
            //   894c2438             | mov                 dword ptr [esp + 0x38], ecx
            //   ffd2                 | call                edx
            //   83ec04               | sub                 esp, 4
            //   31c9                 | xor                 ecx, ecx

        $sequence_12 = { 83c61c 89442444 89c8 83c014 }
            // n = 4, score = 100
            //   83c61c               | add                 esi, 0x1c
            //   89442444             | mov                 dword ptr [esp + 0x44], eax
            //   89c8                 | mov                 eax, ecx
            //   83c014               | add                 eax, 0x14

        $sequence_13 = { 89442460 e8???????? 89442464 8b442450 }
            // n = 4, score = 100
            //   89442460             | mov                 dword ptr [esp + 0x60], eax
            //   e8????????           |                     
            //   89442464             | mov                 dword ptr [esp + 0x64], eax
            //   8b442450             | mov                 eax, dword ptr [esp + 0x50]

        $sequence_14 = { 8b44241c 8b4c2420 8b542424 83fa00 89442418 }
            // n = 5, score = 100
            //   8b44241c             | mov                 eax, dword ptr [esp + 0x1c]
            //   8b4c2420             | mov                 ecx, dword ptr [esp + 0x20]
            //   8b542424             | mov                 edx, dword ptr [esp + 0x24]
            //   83fa00               | cmp                 edx, 0
            //   89442418             | mov                 dword ptr [esp + 0x18], eax

        $sequence_15 = { 8b442434 8b08 894c2420 8b442420 31c9 }
            // n = 5, score = 100
            //   8b442434             | mov                 eax, dword ptr [esp + 0x34]
            //   8b08                 | mov                 ecx, dword ptr [eax]
            //   894c2420             | mov                 dword ptr [esp + 0x20], ecx
            //   8b442420             | mov                 eax, dword ptr [esp + 0x20]
            //   31c9                 | xor                 ecx, ecx

    condition:
        7 of them and filesize < 1187840
}