rule win_teslacrypt_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        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 = "20230124"
        malpedia_hash = "2ee0eebba83dce3d019a90519f2f972c0fcf9686"
        malpedia_version = "20230125"
        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 = { 51 52 8b5570 0fb6c8 }
            // n = 4, score = 900
            //   51                   | push                ecx
            //   52                   | push                edx
            //   8b5570               | mov                 edx, dword ptr [ebp + 0x70]
            //   0fb6c8               | movzx               ecx, al

        $sequence_1 = { 51 52 8b5550 0fb6c8 }
            // n = 4, score = 900
            //   51                   | push                ecx
            //   52                   | push                edx
            //   8b5550               | mov                 edx, dword ptr [ebp + 0x50]
            //   0fb6c8               | movzx               ecx, al

        $sequence_2 = { 334500 335d04 8b542418 8902 895a04 897208 897a0c }
            // n = 7, score = 900
            //   334500               | xor                 eax, dword ptr [ebp]
            //   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

        $sequence_3 = { 55 53 56 57 8b6c2418 c785f0000000e0000000 8b5c2414 }
            // n = 7, score = 900
            //   55                   | push                ebp
            //   53                   | push                ebx
            //   56                   | push                esi
            //   57                   | push                edi
            //   8b6c2418             | mov                 ebp, dword ptr [esp + 0x18]
            //   c785f0000000e0000000     | mov    dword ptr [ebp + 0xf0], 0xe0
            //   8b5c2414             | mov                 ebx, dword ptr [esp + 0x14]

        $sequence_4 = { 335d04 83c510 8b7508 8b7d0c 55 c1c310 0fb6e9 }
            // n = 7, score = 900
            //   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
            //   0fb6e9               | movzx               ebp, cl

        $sequence_5 = { 56 57 8b742414 8b06 8b5e04 8b4e08 8b560c }
            // n = 7, 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]
            //   8b560c               | mov                 edx, dword ptr [esi + 0xc]

        $sequence_6 = { 338594000000 8985b4000000 338598000000 8985b8000000 33859c000000 }
            // n = 5, score = 900
            //   338594000000         | xor                 eax, dword ptr [ebp + 0x94]
            //   8985b4000000         | mov                 dword ptr [ebp + 0xb4], eax
            //   338598000000         | xor                 eax, dword ptr [ebp + 0x98]
            //   8985b8000000         | mov                 dword ptr [ebp + 0xb8], eax
            //   33859c000000         | xor                 eax, dword ptr [ebp + 0x9c]

        $sequence_7 = { 0f84ae010000 81ffe0000000 740a b8ffffffff e9???????? 83c510 8b7508 }
            // n = 7, score = 900
            //   0f84ae010000         | je                  0x1b4
            //   81ffe0000000         | cmp                 edi, 0xe0
            //   740a                 | je                  0xc
            //   b8ffffffff           | mov                 eax, 0xffffffff
            //   e9????????           |                     
            //   83c510               | add                 ebp, 0x10
            //   8b7508               | mov                 esi, dword ptr [ebp + 8]

        $sequence_8 = { 8b91c0000000 8bb1c4000000 8b3d???????? 8b5f4c 891c24 89442430 8954242c }
            // n = 7, score = 100
            //   8b91c0000000         | mov                 edx, dword ptr [ecx + 0xc0]
            //   8bb1c4000000         | mov                 esi, dword ptr [ecx + 0xc4]
            //   8b3d????????         |                     
            //   8b5f4c               | mov                 ebx, dword ptr [edi + 0x4c]
            //   891c24               | mov                 dword ptr [esp], ebx
            //   89442430             | mov                 dword ptr [esp + 0x30], eax
            //   8954242c             | mov                 dword ptr [esp + 0x2c], edx

        $sequence_9 = { 89442418 83c434 5e 5f 5b c3 }
            // n = 6, score = 100
            //   89442418             | mov                 dword ptr [esp + 0x18], eax
            //   83c434               | add                 esp, 0x34
            //   5e                   | pop                 esi
            //   5f                   | pop                 edi
            //   5b                   | pop                 ebx
            //   c3                   | ret                 

        $sequence_10 = { e8???????? 89e0 8d8c24b8000000 89480c 8b4c2468 8908 }
            // n = 6, score = 100
            //   e8????????           |                     
            //   89e0                 | mov                 eax, esp
            //   8d8c24b8000000       | lea                 ecx, [esp + 0xb8]
            //   89480c               | mov                 dword ptr [eax + 0xc], ecx
            //   8b4c2468             | mov                 ecx, dword ptr [esp + 0x68]
            //   8908                 | mov                 dword ptr [eax], ecx

        $sequence_11 = { 83fa00 89442418 894c2414 89542410 7d23 8b442410 25ffff0000 }
            // n = 7, score = 100
            //   83fa00               | cmp                 edx, 0
            //   89442418             | mov                 dword ptr [esp + 0x18], eax
            //   894c2414             | mov                 dword ptr [esp + 0x14], ecx
            //   89542410             | mov                 dword ptr [esp + 0x10], edx
            //   7d23                 | jge                 0x25
            //   8b442410             | mov                 eax, dword ptr [esp + 0x10]
            //   25ffff0000           | and                 eax, 0xffff

        $sequence_12 = { 31c9 8b54247c 8b7250 8b7c2468 893c24 c744240400000000 }
            // n = 6, score = 100
            //   31c9                 | xor                 ecx, ecx
            //   8b54247c             | mov                 edx, dword ptr [esp + 0x7c]
            //   8b7250               | mov                 esi, dword ptr [edx + 0x50]
            //   8b7c2468             | mov                 edi, dword ptr [esp + 0x68]
            //   893c24               | mov                 dword ptr [esp], edi
            //   c744240400000000     | mov                 dword ptr [esp + 4], 0

        $sequence_13 = { 897c2430 8974242c 0f84d3000000 8b44243c 83c008 8b4c242c }
            // n = 6, score = 100
            //   897c2430             | mov                 dword ptr [esp + 0x30], edi
            //   8974242c             | mov                 dword ptr [esp + 0x2c], esi
            //   0f84d3000000         | je                  0xd9
            //   8b44243c             | mov                 eax, dword ptr [esp + 0x3c]
            //   83c008               | add                 eax, 8
            //   8b4c242c             | mov                 ecx, dword ptr [esp + 0x2c]

        $sequence_14 = { 89442404 75ad 8a442403 a801 7505 e9???????? 8b44240c }
            // n = 7, score = 100
            //   89442404             | mov                 dword ptr [esp + 4], eax
            //   75ad                 | jne                 0xffffffaf
            //   8a442403             | mov                 al, byte ptr [esp + 3]
            //   a801                 | test                al, 1
            //   7505                 | jne                 7
            //   e9????????           |                     
            //   8b44240c             | mov                 eax, dword ptr [esp + 0xc]

        $sequence_15 = { e8???????? 8b4c2468 8b54247c 034a44 8b726c 89b42480000000 }
            // n = 6, score = 100
            //   e8????????           |                     
            //   8b4c2468             | mov                 ecx, dword ptr [esp + 0x68]
            //   8b54247c             | mov                 edx, dword ptr [esp + 0x7c]
            //   034a44               | add                 ecx, dword ptr [edx + 0x44]
            //   8b726c               | mov                 esi, dword ptr [edx + 0x6c]
            //   89b42480000000       | mov                 dword ptr [esp + 0x80], esi

    condition:
        7 of them and filesize < 1187840
}