rule win_rc2fm_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-01-25"
        version = "1"
        description = "Detects win.rc2fm."
        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.rc2fm"
        malpedia_rule_date = "20230124"
        malpedia_hash = "2ee0eebba83dce3d019a90519f2f972c0fcf9686"
        malpedia_version = "20230125"
        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 = { 0f85c8000000 488b4330 48396810 0f84b3000000 0fb74018 448b5328 }
            // n = 6, score = 100
            //   0f85c8000000         | dec                 ecx
            //   488b4330             | dec                 edi
            //   48396810             | jne                 0xec8
            //   0f84b3000000         | inc                 ebp
            //   0fb74018             | test                ah, ah
            //   448b5328             | dec                 ecx

        $sequence_1 = { b900000000 85c0 0f48c1 488b8c2488000000 8901 4883c448 415d }
            // n = 7, score = 100
            //   b900000000           | dec                 esp
            //   85c0                 | mov                 edi, dword ptr [esp + 0x100]
            //   0f48c1               | jmp                 0x1ec1
            //   488b8c2488000000     | mov                 edx, 0xb0002
            //   8901                 | jmp                 0x1eae
            //   4883c448             | dec                 esp
            //   415d                 | mov                 edi, dword ptr [esp + 0x110]

        $sequence_2 = { c1c80b 0fb6c9 4883c206 03c1 49ffc9 7580 3dc6adb1fd }
            // n = 7, score = 100
            //   c1c80b               | je                  0x139
            //   0fb6c9               | dec                 esp
            //   4883c206             | mov                 eax, dword ptr [edi]
            //   03c1                 | add                 esi, eax
            //   49ffc9               | lea                 eax, [esi + 1]
            //   7580                 | dec                 esp
            //   3dc6adb1fd           | arpl                ax, ax

        $sequence_3 = { e8???????? 488b0d???????? e8???????? 48c705????????00000000 eb12 448bc0 ba01000000 }
            // n = 7, score = 100
            //   e8????????           |                     
            //   488b0d????????       |                     
            //   e8????????           |                     
            //   48c705????????00000000     |     
            //   eb12                 | mov                 edx, esp
            //   448bc0               | dec                 eax
            //   ba01000000           | mov                 dword ptr [ebp + 0x100], 2

        $sequence_4 = { 415d 5d c3 b002 ebe7 b001 }
            // n = 6, score = 100
            //   415d                 | mov                 esi, ecx
            //   5d                   | push                edi
            //   c3                   | dec                 eax
            //   b002                 | sub                 esp, 0x20
            //   ebe7                 | mov                 eax, dword ptr [ecx + 0x18]
            //   b001                 | dec                 eax

        $sequence_5 = { 83f810 7707 bb10000000 eb0f bb18000000 83f818 7605 }
            // n = 7, score = 100
            //   83f810               | mov                 dword ptr [ebp - 0x28], 0x78007a
            //   7707                 | mov                 dword ptr [ebp - 0x24], 0x760063
            //   bb10000000           | mov                 dword ptr [ebp - 0x20], 0x6e0062
            //   eb0f                 | mov                 dword ptr [ebp - 0x1c], 0x31006d
            //   bb18000000           | mov                 dword ptr [ebp - 0x2d], 0x10000
            //   83f818               | mov                 dword ptr [ebp - 0x28], 0
            //   7605                 | dec                 eax

        $sequence_6 = { 0fb74302 4883c302 6685c0 75ed e9???????? 498bd5 b912040000 }
            // n = 7, score = 100
            //   0fb74302             | jmp                 0x11bc
            //   4883c302             | mov                 edx, 0x60002
            //   6685c0               | dec                 esp
            //   75ed                 | mov                 eax, edi
            //   e9????????           |                     
            //   498bd5               | dec                 eax
            //   b912040000           | mov                 edi, dword ptr [edi + 0x10]

        $sequence_7 = { 4c8b05???????? 4d85c0 7420 488b0d???????? 33d2 ff15???????? eb0f }
            // n = 7, score = 100
            //   4c8b05????????       |                     
            //   4d85c0               | jmp                 0x5e
            //   7420                 | test                eax, eax
            //   488b0d????????       |                     
            //   33d2                 | jne                 0x4f
            //   ff15????????         |                     
            //   eb0f                 | dec                 ecx

        $sequence_8 = { ff15???????? eb18 ff15???????? ba02000400 b914000100 448bc0 e8???????? }
            // n = 7, score = 100
            //   ff15????????         |                     
            //   eb18                 | je                  0x189c
            //   ff15????????         |                     
            //   ba02000400           | cmp                 eax, ebx
            //   b914000100           | inc                 eax
            //   448bc0               | xor                 bh, bh
            //   e8????????           |                     

        $sequence_9 = { 4032f6 488d55f7 b903000000 ff15???????? 488b4d8f 488b01 ff5010 }
            // n = 7, score = 100
            //   4032f6               | mov                 esi, dword ptr [esp + 0x40]
            //   488d55f7             | dec                 eax
            //   b903000000           | add                 esp, 0x20
            //   ff15????????         |                     
            //   488b4d8f             | inc                 ecx
            //   488b01               | pop                 esi
            //   ff5010               | ret                 

    condition:
        7 of them and filesize < 410624
}