rule win_locky_decryptor_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.locky_decryptor."
        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.locky_decryptor"
        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 = { 3b45d8 0f8417ffffff 8b45dc 89855cffffff 8b45e0 8945d0 }
            // n = 6, score = 100
            //   3b45d8               | cmp                 eax, dword ptr [ebp - 0x28]
            //   0f8417ffffff         | je                  0xffffff1d
            //   8b45dc               | mov                 eax, dword ptr [ebp - 0x24]
            //   89855cffffff         | mov                 dword ptr [ebp - 0xa4], eax
            //   8b45e0               | mov                 eax, dword ptr [ebp - 0x20]
            //   8945d0               | mov                 dword ptr [ebp - 0x30], eax

        $sequence_1 = { c605????????01 e8???????? 6a07 58 33db 33c9 }
            // n = 6, score = 100
            //   c605????????01       |                     
            //   e8????????           |                     
            //   6a07                 | push                7
            //   58                   | pop                 eax
            //   33db                 | xor                 ebx, ebx
            //   33c9                 | xor                 ecx, ecx

        $sequence_2 = { 8bc6 c9 c21000 ff15???????? 50 }
            // n = 5, score = 100
            //   8bc6                 | mov                 eax, esi
            //   c9                   | leave               
            //   c21000               | ret                 0x10
            //   ff15????????         |                     
            //   50                   | push                eax

        $sequence_3 = { 8b4508 eb29 ff75e8 8b7508 8d8405ccfaffff 50 }
            // n = 6, score = 100
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   eb29                 | jmp                 0x2b
            //   ff75e8               | push                dword ptr [ebp - 0x18]
            //   8b7508               | mov                 esi, dword ptr [ebp + 8]
            //   8d8405ccfaffff       | lea                 eax, [ebp + eax - 0x534]
            //   50                   | push                eax

        $sequence_4 = { 89450c 57 8d4510 7203 8d450c 8b38 8d75d8 }
            // n = 7, score = 100
            //   89450c               | mov                 dword ptr [ebp + 0xc], eax
            //   57                   | push                edi
            //   8d4510               | lea                 eax, [ebp + 0x10]
            //   7203                 | jb                  5
            //   8d450c               | lea                 eax, [ebp + 0xc]
            //   8b38                 | mov                 edi, dword ptr [eax]
            //   8d75d8               | lea                 esi, [ebp - 0x28]

        $sequence_5 = { c20c00 55 8bec 8b00 83ec10 6a00 8d4d0c }
            // n = 7, score = 100
            //   c20c00               | ret                 0xc
            //   55                   | push                ebp
            //   8bec                 | mov                 ebp, esp
            //   8b00                 | mov                 eax, dword ptr [eax]
            //   83ec10               | sub                 esp, 0x10
            //   6a00                 | push                0
            //   8d4d0c               | lea                 ecx, [ebp + 0xc]

        $sequence_6 = { 7418 56 56 56 8d85a8f7ffff 50 }
            // n = 6, score = 100
            //   7418                 | je                  0x1a
            //   56                   | push                esi
            //   56                   | push                esi
            //   56                   | push                esi
            //   8d85a8f7ffff         | lea                 eax, [ebp - 0x858]
            //   50                   | push                eax

        $sequence_7 = { 83c058 0fb691106b4100 660f6fc8 660f73f904 660fefc1 660f6fc8 }
            // n = 6, score = 100
            //   83c058               | add                 eax, 0x58
            //   0fb691106b4100       | movzx               edx, byte ptr [ecx + 0x416b10]
            //   660f6fc8             | movdqa              xmm1, xmm0
            //   660f73f904           | pslldq              xmm1, 4
            //   660fefc1             | pxor                xmm0, xmm1
            //   660f6fc8             | movdqa              xmm1, xmm0

        $sequence_8 = { 7209 83ffff 0f879c000000 8d742424 e8???????? c644244c01 85db }
            // n = 7, score = 100
            //   7209                 | jb                  0xb
            //   83ffff               | cmp                 edi, -1
            //   0f879c000000         | ja                  0xa2
            //   8d742424             | lea                 esi, [esp + 0x24]
            //   e8????????           |                     
            //   c644244c01           | mov                 byte ptr [esp + 0x4c], 1
            //   85db                 | test                ebx, ebx

        $sequence_9 = { ff75f4 ff55f8 85c0 743f be???????? 8d4590 }
            // n = 6, score = 100
            //   ff75f4               | push                dword ptr [ebp - 0xc]
            //   ff55f8               | call                dword ptr [ebp - 8]
            //   85c0                 | test                eax, eax
            //   743f                 | je                  0x41
            //   be????????           |                     
            //   8d4590               | lea                 eax, [ebp - 0x70]

    condition:
        7 of them and filesize < 278528
}