rule win_cryptolocker_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-03-28"
        version = "1"
        description = "Detects win.cryptolocker."
        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.cryptolocker"
        malpedia_rule_date = "20230328"
        malpedia_hash = "9d2d75cef573c1c2d861f5197df8f563b05a305d"
        malpedia_version = "20230407"
        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 = { 753d 8b4510 833804 7417 32c0 0fb6c8 33c0 }
            // n = 7, score = 600
            //   753d                 | jne                 0x3f
            //   8b4510               | mov                 eax, dword ptr [ebp + 0x10]
            //   833804               | cmp                 dword ptr [eax], 4
            //   7417                 | je                  0x19
            //   32c0                 | xor                 al, al
            //   0fb6c8               | movzx               ecx, al
            //   33c0                 | xor                 eax, eax

        $sequence_1 = { 85f6 7413 f6c301 7407 56 ff15???????? 56 }
            // n = 7, score = 600
            //   85f6                 | test                esi, esi
            //   7413                 | je                  0x15
            //   f6c301               | test                bl, 1
            //   7407                 | je                  9
            //   56                   | push                esi
            //   ff15????????         |                     
            //   56                   | push                esi

        $sequence_2 = { 7517 53 50 ff35???????? ff15???????? 5b 5f }
            // n = 7, score = 600
            //   7517                 | jne                 0x19
            //   53                   | push                ebx
            //   50                   | push                eax
            //   ff35????????         |                     
            //   ff15????????         |                     
            //   5b                   | pop                 ebx
            //   5f                   | pop                 edi

        $sequence_3 = { 7415 8b4664 85c0 740e 50 ff15???????? }
            // n = 6, score = 600
            //   7415                 | je                  0x17
            //   8b4664               | mov                 eax, dword ptr [esi + 0x64]
            //   85c0                 | test                eax, eax
            //   740e                 | je                  0x10
            //   50                   | push                eax
            //   ff15????????         |                     

        $sequence_4 = { 5f 5d c20400 8b4710 8bd9 c7400c00000000 }
            // n = 6, score = 600
            //   5f                   | pop                 edi
            //   5d                   | pop                 ebp
            //   c20400               | ret                 4
            //   8b4710               | mov                 eax, dword ptr [edi + 0x10]
            //   8bd9                 | mov                 ebx, ecx
            //   c7400c00000000       | mov                 dword ptr [eax + 0xc], 0

        $sequence_5 = { be08000000 85ff 7413 f6c301 7407 57 ff15???????? }
            // n = 7, score = 600
            //   be08000000           | mov                 esi, 8
            //   85ff                 | test                edi, edi
            //   7413                 | je                  0x15
            //   f6c301               | test                bl, 1
            //   7407                 | je                  9
            //   57                   | push                edi
            //   ff15????????         |                     

        $sequence_6 = { 8bf1 57 8bfa 85f6 7452 8a06 }
            // n = 6, score = 600
            //   8bf1                 | mov                 esi, ecx
            //   57                   | push                edi
            //   8bfa                 | mov                 edi, edx
            //   85f6                 | test                esi, esi
            //   7452                 | je                  0x54
            //   8a06                 | mov                 al, byte ptr [esi]

        $sequence_7 = { 33c0 8bf2 85ff 7504 }
            // n = 4, score = 600
            //   33c0                 | xor                 eax, eax
            //   8bf2                 | mov                 esi, edx
            //   85ff                 | test                edi, edi
            //   7504                 | jne                 6

        $sequence_8 = { 8b4d10 f6c101 7556 8b450c 83f801 7405 83f802 }
            // n = 7, score = 600
            //   8b4d10               | mov                 ecx, dword ptr [ebp + 0x10]
            //   f6c101               | test                cl, 1
            //   7556                 | jne                 0x58
            //   8b450c               | mov                 eax, dword ptr [ebp + 0xc]
            //   83f801               | cmp                 eax, 1
            //   7405                 | je                  7
            //   83f802               | cmp                 eax, 2

        $sequence_9 = { 5d c21800 8b451c f6400c10 7433 5f 5e }
            // n = 7, score = 600
            //   5d                   | pop                 ebp
            //   c21800               | ret                 0x18
            //   8b451c               | mov                 eax, dword ptr [ebp + 0x1c]
            //   f6400c10             | test                byte ptr [eax + 0xc], 0x10
            //   7433                 | je                  0x35
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi

    condition:
        7 of them and filesize < 778240
}