rule win_ramsay_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-03-28"
        version = "1"
        description = "Detects win.ramsay."
        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.ramsay"
        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 = { 83f820 7502 eb07 33c0 e9???????? }
            // n = 5, score = 600
            //   83f820               | cmp                 eax, 0x20
            //   7502                 | jne                 4
            //   eb07                 | jmp                 9
            //   33c0                 | xor                 eax, eax
            //   e9????????           |                     

        $sequence_1 = { 85c0 7514 ff15???????? 83f820 7502 }
            // n = 5, score = 600
            //   85c0                 | test                eax, eax
            //   7514                 | jne                 0x16
            //   ff15????????         |                     
            //   83f820               | cmp                 eax, 0x20
            //   7502                 | jne                 4

        $sequence_2 = { ff15???????? 85c0 7502 eb02 ebb1 }
            // n = 5, score = 600
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   7502                 | jne                 4
            //   eb02                 | jmp                 4
            //   ebb1                 | jmp                 0xffffffb3

        $sequence_3 = { 8d45f0 50 8b4dfc 51 e8???????? 83f86f }
            // n = 6, score = 500
            //   8d45f0               | lea                 eax, [ebp - 0x10]
            //   50                   | push                eax
            //   8b4dfc               | mov                 ecx, dword ptr [ebp - 4]
            //   51                   | push                ecx
            //   e8????????           |                     
            //   83f86f               | cmp                 eax, 0x6f

        $sequence_4 = { c745f088020000 c745f400000000 6888020000 e8???????? 83c404 8945fc }
            // n = 6, score = 500
            //   c745f088020000       | mov                 dword ptr [ebp - 0x10], 0x288
            //   c745f400000000       | mov                 dword ptr [ebp - 0xc], 0
            //   6888020000           | push                0x288
            //   e8????????           |                     
            //   83c404               | add                 esp, 4
            //   8945fc               | mov                 dword ptr [ebp - 4], eax

        $sequence_5 = { 8b4d08 034df8 8b55e8 0355f8 8a8294010000 8801 ebd3 }
            // n = 7, score = 500
            //   8b4d08               | mov                 ecx, dword ptr [ebp + 8]
            //   034df8               | add                 ecx, dword ptr [ebp - 8]
            //   8b55e8               | mov                 edx, dword ptr [ebp - 0x18]
            //   0355f8               | add                 edx, dword ptr [ebp - 8]
            //   8a8294010000         | mov                 al, byte ptr [edx + 0x194]
            //   8801                 | mov                 byte ptr [ecx], al
            //   ebd3                 | jmp                 0xffffffd5

        $sequence_6 = { 83bdc4fdffffff 7507 33c0 e9???????? }
            // n = 4, score = 500
            //   83bdc4fdffffff       | cmp                 dword ptr [ebp - 0x23c], -1
            //   7507                 | jne                 9
            //   33c0                 | xor                 eax, eax
            //   e9????????           |                     

        $sequence_7 = { 8b5508 8b4508 8a480b 884a1e 8b5508 8b4508 8a481c }
            // n = 7, score = 500
            //   8b5508               | mov                 edx, dword ptr [ebp + 8]
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   8a480b               | mov                 cl, byte ptr [eax + 0xb]
            //   884a1e               | mov                 byte ptr [edx + 0x1e], cl
            //   8b5508               | mov                 edx, dword ptr [ebp + 8]
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   8a481c               | mov                 cl, byte ptr [eax + 0x1c]

        $sequence_8 = { 8b4de8 8b11 8955e8 eba5 }
            // n = 4, score = 500
            //   8b4de8               | mov                 ecx, dword ptr [ebp - 0x18]
            //   8b11                 | mov                 edx, dword ptr [ecx]
            //   8955e8               | mov                 dword ptr [ebp - 0x18], edx
            //   eba5                 | jmp                 0xffffffa7

        $sequence_9 = { 8b5508 8b4508 8a4815 884a1e }
            // n = 4, score = 500
            //   8b5508               | mov                 edx, dword ptr [ebp + 8]
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   8a4815               | mov                 cl, byte ptr [eax + 0x15]
            //   884a1e               | mov                 byte ptr [edx + 0x1e], cl

        $sequence_10 = { d1e2 52 6a00 8b45fc }
            // n = 4, score = 500
            //   d1e2                 | shl                 edx, 1
            //   52                   | push                edx
            //   6a00                 | push                0
            //   8b45fc               | mov                 eax, dword ptr [ebp - 4]

        $sequence_11 = { ff15???????? 33c0 e9???????? e8???????? 85c0 7507 33c0 }
            // n = 7, score = 400
            //   ff15????????         |                     
            //   33c0                 | xor                 eax, eax
            //   e9????????           |                     
            //   e8????????           |                     
            //   85c0                 | test                eax, eax
            //   7507                 | jne                 9
            //   33c0                 | xor                 eax, eax

        $sequence_12 = { e8???????? e8???????? 448b4c2428 4c8bc0 }
            // n = 4, score = 200
            //   e8????????           |                     
            //   e8????????           |                     
            //   448b4c2428           | lea                 eax, [esp + 0x4e2]
            //   4c8bc0               | dec                 eax

        $sequence_13 = { e8???????? e8???????? 0fb78424c6040000 99 b905000000 f7f9 }
            // n = 6, score = 200
            //   e8????????           |                     
            //   e8????????           |                     
            //   0fb78424c6040000     | movzx               eax, word ptr [esp + 0x4c6]
            //   99                   | cdq                 
            //   b905000000           | mov                 ecx, 5
            //   f7f9                 | idiv                ecx

        $sequence_14 = { e8???????? e8???????? 488b8c2450020000 4833cc }
            // n = 4, score = 200
            //   e8????????           |                     
            //   e8????????           |                     
            //   488b8c2450020000     | mov                 eax, eax
            //   4833cc               | inc                 esp

        $sequence_15 = { e8???????? e8???????? 33c0 6689442440 }
            // n = 4, score = 200
            //   e8????????           |                     
            //   e8????????           |                     
            //   33c0                 | xor                 eax, eax
            //   6689442440           | mov                 word ptr [esp + 0x40], ax

    condition:
        7 of them and filesize < 2031616
}