rule win_ragnarok_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-07-11"
        version = "1"
        description = "Detects win.ragnarok."
        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.ragnarok"
        malpedia_rule_date = "20230705"
        malpedia_hash = "42d0574f4405bd7d2b154d321d345acb18834a41"
        malpedia_version = "20230715"
        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 = { c1e908 0fb6c9 c1e208 0fb689105c4300 33d1 8b4de8 }
            // n = 6, score = 200
            //   c1e908               | shr                 ecx, 8
            //   0fb6c9               | movzx               ecx, cl
            //   c1e208               | shl                 edx, 8
            //   0fb689105c4300       | movzx               ecx, byte ptr [ecx + 0x435c10]
            //   33d1                 | xor                 edx, ecx
            //   8b4de8               | mov                 ecx, dword ptr [ebp - 0x18]

        $sequence_1 = { 83ec08 53 56 57 6a1e ff35???????? e8???????? }
            // n = 7, score = 200
            //   83ec08               | sub                 esp, 8
            //   53                   | push                ebx
            //   56                   | push                esi
            //   57                   | push                edi
            //   6a1e                 | push                0x1e
            //   ff35????????         |                     
            //   e8????????           |                     

        $sequence_2 = { 33348d10584300 8b4dec 8b149510544300 0fb6c9 33348d104c4300 }
            // n = 5, score = 200
            //   33348d10584300       | xor                 esi, dword ptr [ecx*4 + 0x435810]
            //   8b4dec               | mov                 ecx, dword ptr [ebp - 0x14]
            //   8b149510544300       | mov                 edx, dword ptr [edx*4 + 0x435410]
            //   0fb6c9               | movzx               ecx, cl
            //   33348d104c4300       | xor                 esi, dword ptr [ecx*4 + 0x434c10]

        $sequence_3 = { 55 8bec 83ec18 53 56 8b7510 8bc6 }
            // n = 7, score = 200
            //   55                   | push                ebp
            //   8bec                 | mov                 ebp, esp
            //   83ec18               | sub                 esp, 0x18
            //   53                   | push                ebx
            //   56                   | push                esi
            //   8b7510               | mov                 esi, dword ptr [ebp + 0x10]
            //   8bc6                 | mov                 eax, esi

        $sequence_4 = { 8b4dfc 0fb6c9 0fb689104b4300 c1e108 33f9 8b4dfc c1e910 }
            // n = 7, score = 200
            //   8b4dfc               | mov                 ecx, dword ptr [ebp - 4]
            //   0fb6c9               | movzx               ecx, cl
            //   0fb689104b4300       | movzx               ecx, byte ptr [ecx + 0x434b10]
            //   c1e108               | shl                 ecx, 8
            //   33f9                 | xor                 edi, ecx
            //   8b4dfc               | mov                 ecx, dword ptr [ebp - 4]
            //   c1e910               | shr                 ecx, 0x10

        $sequence_5 = { 51 ff35???????? ffd6 6a1a ff35???????? 8bd8 e8???????? }
            // n = 7, score = 200
            //   51                   | push                ecx
            //   ff35????????         |                     
            //   ffd6                 | call                esi
            //   6a1a                 | push                0x1a
            //   ff35????????         |                     
            //   8bd8                 | mov                 ebx, eax
            //   e8????????           |                     

        $sequence_6 = { f3a5 8bca 8945f8 83e103 f3a4 3b450c 7ca5 }
            // n = 7, score = 200
            //   f3a5                 | rep movsd           dword ptr es:[edi], dword ptr [esi]
            //   8bca                 | mov                 ecx, edx
            //   8945f8               | mov                 dword ptr [ebp - 8], eax
            //   83e103               | and                 ecx, 3
            //   f3a4                 | rep movsb           byte ptr es:[edi], byte ptr [esi]
            //   3b450c               | cmp                 eax, dword ptr [ebp + 0xc]
            //   7ca5                 | jl                  0xffffffa7

        $sequence_7 = { c1c009 f7d1 234db0 03c7 8945a4 8b45a0 2345b4 }
            // n = 7, score = 200
            //   c1c009               | rol                 eax, 9
            //   f7d1                 | not                 ecx
            //   234db0               | and                 ecx, dword ptr [ebp - 0x50]
            //   03c7                 | add                 eax, edi
            //   8945a4               | mov                 dword ptr [ebp - 0x5c], eax
            //   8b45a0               | mov                 eax, dword ptr [ebp - 0x60]
            //   2345b4               | and                 eax, dword ptr [ebp - 0x4c]

        $sequence_8 = { 660fd60f 8d7f08 8b048dd4314100 ffe0 f7c703000000 7413 8a06 }
            // n = 7, score = 200
            //   660fd60f             | movq                qword ptr [edi], xmm1
            //   8d7f08               | lea                 edi, [edi + 8]
            //   8b048dd4314100       | mov                 eax, dword ptr [ecx*4 + 0x4131d4]
            //   ffe0                 | jmp                 eax
            //   f7c703000000         | test                edi, 3
            //   7413                 | je                  0x15
            //   8a06                 | mov                 al, byte ptr [esi]

        $sequence_9 = { 2d80000000 742b 83e840 741b 83e840 }
            // n = 5, score = 200
            //   2d80000000           | sub                 eax, 0x80
            //   742b                 | je                  0x2d
            //   83e840               | sub                 eax, 0x40
            //   741b                 | je                  0x1d
            //   83e840               | sub                 eax, 0x40

    condition:
        7 of them and filesize < 483328
}