rule win_crypt0l0cker_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.crypt0l0cker."
        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.crypt0l0cker"
        malpedia_rule_date = "20260916"
        malpedia_hash = "53a643781c18e08f4a50949af60172d837a0b6f6"
        malpedia_version = "20260917"
        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 = { 55 6a00 ff35???????? ff15???????? 8bf0 85f6 0f84c0000000 }
            // n = 7, score = 100
            //   55                   | push                ebp
            //   6a00                 | push                0
            //   ff35????????         |                     
            //   ff15????????         |                     
            //   8bf0                 | mov                 esi, eax
            //   85f6                 | test                esi, esi
            //   0f84c0000000         | je                  0xc6

        $sequence_1 = { 7409 80f917 0f85b8000000 51 8b0f }
            // n = 5, score = 100
            //   7409                 | je                  0xb
            //   80f917               | cmp                 cl, 0x17
            //   0f85b8000000         | jne                 0xbe
            //   51                   | push                ecx
            //   8b0f                 | mov                 ecx, dword ptr [edi]

        $sequence_2 = { 8bcf e8???????? 85c0 74e3 8b4508 33c9 8b13 }
            // n = 7, score = 100
            //   8bcf                 | mov                 ecx, edi
            //   e8????????           |                     
            //   85c0                 | test                eax, eax
            //   74e3                 | je                  0xffffffe5
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   33c9                 | xor                 ecx, ecx
            //   8b13                 | mov                 edx, dword ptr [ebx]

        $sequence_3 = { 8d542428 8bce e8???????? 8944241c 85c0 0f845b020000 55 }
            // n = 7, score = 100
            //   8d542428             | lea                 edx, [esp + 0x28]
            //   8bce                 | mov                 ecx, esi
            //   e8????????           |                     
            //   8944241c             | mov                 dword ptr [esp + 0x1c], eax
            //   85c0                 | test                eax, eax
            //   0f845b020000         | je                  0x261
            //   55                   | push                ebp

        $sequence_4 = { 85c0 756c 8bb538fdffff 83bdd4fcffff01 750c ffb5dcfcffff e8???????? }
            // n = 7, score = 100
            //   85c0                 | test                eax, eax
            //   756c                 | jne                 0x6e
            //   8bb538fdffff         | mov                 esi, dword ptr [ebp - 0x2c8]
            //   83bdd4fcffff01       | cmp                 dword ptr [ebp - 0x32c], 1
            //   750c                 | jne                 0xe
            //   ffb5dcfcffff         | push                dword ptr [ebp - 0x324]
            //   e8????????           |                     

        $sequence_5 = { 03d9 3bd9 7301 47 8b4508 0fb75012 0fb74810 }
            // n = 7, score = 100
            //   03d9                 | add                 ebx, ecx
            //   3bd9                 | cmp                 ebx, ecx
            //   7301                 | jae                 3
            //   47                   | inc                 edi
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   0fb75012             | movzx               edx, word ptr [eax + 0x12]
            //   0fb74810             | movzx               ecx, word ptr [eax + 0x10]

        $sequence_6 = { 8b542450 e8???????? 83c420 f646f802 742e }
            // n = 5, score = 100
            //   8b542450             | mov                 edx, dword ptr [esp + 0x50]
            //   e8????????           |                     
            //   83c420               | add                 esp, 0x20
            //   f646f802             | test                byte ptr [esi - 8], 2
            //   742e                 | je                  0x30

        $sequence_7 = { 6a20 e8???????? 83c410 8bc6 5f 5e 5b }
            // n = 7, score = 100
            //   6a20                 | push                0x20
            //   e8????????           |                     
            //   83c410               | add                 esp, 0x10
            //   8bc6                 | mov                 eax, esi
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi
            //   5b                   | pop                 ebx

        $sequence_8 = { 8974241c ff15???????? 85c0 741f 8b442420 85c0 7406 }
            // n = 7, score = 100
            //   8974241c             | mov                 dword ptr [esp + 0x1c], esi
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   741f                 | je                  0x21
            //   8b442420             | mov                 eax, dword ptr [esp + 0x20]
            //   85c0                 | test                eax, eax
            //   7406                 | je                  8

        $sequence_9 = { 83c1fe 85c9 7e10 8d642400 66833c4a2e 7409 49 }
            // n = 7, score = 100
            //   83c1fe               | add                 ecx, -2
            //   85c9                 | test                ecx, ecx
            //   7e10                 | jle                 0x12
            //   8d642400             | lea                 esp, [esp]
            //   66833c4a2e           | cmp                 word ptr [edx + ecx*2], 0x2e
            //   7409                 | je                  0xb
            //   49                   | dec                 ecx

    condition:
        7 of them and filesize < 917504
}