rule win_medusalocker_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-03-28"
        version = "1"
        description = "Detects win.medusalocker."
        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.medusalocker"
        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 = { 8b4d0c 8d1441 52 8b450c 50 8b4d08 e8???????? }
            // n = 7, score = 400
            //   8b4d0c               | mov                 ecx, dword ptr [ebp + 0xc]
            //   8d1441               | lea                 edx, [ecx + eax*2]
            //   52                   | push                edx
            //   8b450c               | mov                 eax, dword ptr [ebp + 0xc]
            //   50                   | push                eax
            //   8b4d08               | mov                 ecx, dword ptr [ebp + 8]
            //   e8????????           |                     

        $sequence_1 = { 7411 8b45f0 8b08 e8???????? 0fb6c8 85c9 7509 }
            // n = 7, score = 400
            //   7411                 | je                  0x13
            //   8b45f0               | mov                 eax, dword ptr [ebp - 0x10]
            //   8b08                 | mov                 ecx, dword ptr [eax]
            //   e8????????           |                     
            //   0fb6c8               | movzx               ecx, al
            //   85c9                 | test                ecx, ecx
            //   7509                 | jne                 0xb

        $sequence_2 = { 8b450c 50 e8???????? 83c408 50 8d4de4 }
            // n = 6, score = 400
            //   8b450c               | mov                 eax, dword ptr [ebp + 0xc]
            //   50                   | push                eax
            //   e8????????           |                     
            //   83c408               | add                 esp, 8
            //   50                   | push                eax
            //   8d4de4               | lea                 ecx, [ebp - 0x1c]

        $sequence_3 = { 8b55f4 d3ea 83e23f 81ca80000000 8b4520 8b08 8811 }
            // n = 7, score = 400
            //   8b55f4               | mov                 edx, dword ptr [ebp - 0xc]
            //   d3ea                 | shr                 edx, cl
            //   83e23f               | and                 edx, 0x3f
            //   81ca80000000         | or                  edx, 0x80
            //   8b4520               | mov                 eax, dword ptr [ebp + 0x20]
            //   8b08                 | mov                 ecx, dword ptr [eax]
            //   8811                 | mov                 byte ptr [ecx], dl

        $sequence_4 = { 8b4df8 894810 8b55f8 2b5508 83c201 52 8b450c }
            // n = 7, score = 400
            //   8b4df8               | mov                 ecx, dword ptr [ebp - 8]
            //   894810               | mov                 dword ptr [eax + 0x10], ecx
            //   8b55f8               | mov                 edx, dword ptr [ebp - 8]
            //   2b5508               | sub                 edx, dword ptr [ebp + 8]
            //   83c201               | add                 edx, 1
            //   52                   | push                edx
            //   8b450c               | mov                 eax, dword ptr [ebp + 0xc]

        $sequence_5 = { e8???????? 83c408 50 e8???????? 8d4508 50 8b4df0 }
            // n = 7, score = 400
            //   e8????????           |                     
            //   83c408               | add                 esp, 8
            //   50                   | push                eax
            //   e8????????           |                     
            //   8d4508               | lea                 eax, [ebp + 8]
            //   50                   | push                eax
            //   8b4df0               | mov                 ecx, dword ptr [ebp - 0x10]

        $sequence_6 = { 83c104 e8???????? 8b45fc 8be5 5d c20400 55 }
            // n = 7, score = 400
            //   83c104               | add                 ecx, 4
            //   e8????????           |                     
            //   8b45fc               | mov                 eax, dword ptr [ebp - 4]
            //   8be5                 | mov                 esp, ebp
            //   5d                   | pop                 ebp
            //   c20400               | ret                 4
            //   55                   | push                ebp

        $sequence_7 = { 8d4dd8 e8???????? 83f810 730e 6a00 6a08 }
            // n = 6, score = 400
            //   8d4dd8               | lea                 ecx, [ebp - 0x28]
            //   e8????????           |                     
            //   83f810               | cmp                 eax, 0x10
            //   730e                 | jae                 0x10
            //   6a00                 | push                0
            //   6a08                 | push                8

        $sequence_8 = { 8b8ddcfdffff 83c108 e8???????? c645fc01 8b8ddcfdffff 83c120 e8???????? }
            // n = 7, score = 400
            //   8b8ddcfdffff         | mov                 ecx, dword ptr [ebp - 0x224]
            //   83c108               | add                 ecx, 8
            //   e8????????           |                     
            //   c645fc01             | mov                 byte ptr [ebp - 4], 1
            //   8b8ddcfdffff         | mov                 ecx, dword ptr [ebp - 0x224]
            //   83c120               | add                 ecx, 0x20
            //   e8????????           |                     

        $sequence_9 = { 83c108 51 ff15???????? 85c0 7539 ff15???????? }
            // n = 6, score = 400
            //   83c108               | add                 ecx, 8
            //   51                   | push                ecx
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   7539                 | jne                 0x3b
            //   ff15????????         |                     

    condition:
        7 of them and filesize < 1433600
}