rule win_ramsay_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2022-04-08"
        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 = "20220405"
        malpedia_hash = "ecd38294bd47d5589be5cd5490dc8bb4804afc2a"
        malpedia_version = "20220411"
        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 }
            // n = 4, score = 600
            //   83f820               | cmp                 eax, 0x20
            //   7502                 | jne                 4
            //   eb07                 | jmp                 9
            //   33c0                 | xor                 eax, eax

        $sequence_1 = { ff15???????? 85c0 7502 eb02 ebb1 }
            // n = 5, score = 600
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   7502                 | jne                 4
            //   eb02                 | jmp                 4
            //   ebb1                 | jmp                 0xffffffb3

        $sequence_2 = { 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_3 = { c745ec00000000 6a06 8d55f0 52 e8???????? }
            // n = 5, score = 500
            //   c745ec00000000       | mov                 dword ptr [ebp - 0x14], 0
            //   6a06                 | push                6
            //   8d55f0               | lea                 edx, dword ptr [ebp - 0x10]
            //   52                   | push                edx
            //   e8????????           |                     

        $sequence_4 = { 8b4dfc 3b4d08 732c e8???????? }
            // n = 4, score = 500
            //   8b4dfc               | mov                 ecx, dword ptr [ebp - 4]
            //   3b4d08               | cmp                 ecx, dword ptr [ebp + 8]
            //   732c                 | jae                 0x2e
            //   e8????????           |                     

        $sequence_5 = { 33d2 b910000000 f7f1 8955ec 8b5508 0355e8 8b45ec }
            // n = 7, score = 500
            //   33d2                 | xor                 edx, edx
            //   b910000000           | mov                 ecx, 0x10
            //   f7f1                 | div                 ecx
            //   8955ec               | mov                 dword ptr [ebp - 0x14], edx
            //   8b5508               | mov                 edx, dword ptr [ebp + 8]
            //   0355e8               | add                 edx, dword ptr [ebp - 0x18]
            //   8b45ec               | mov                 eax, dword ptr [ebp - 0x14]

        $sequence_6 = { 837dec00 7561 8b45fc 8945e8 837de800 7455 }
            // n = 6, score = 500
            //   837dec00             | cmp                 dword ptr [ebp - 0x14], 0
            //   7561                 | jne                 0x63
            //   8b45fc               | mov                 eax, dword ptr [ebp - 4]
            //   8945e8               | mov                 dword ptr [ebp - 0x18], eax
            //   837de800             | cmp                 dword ptr [ebp - 0x18], 0
            //   7455                 | je                  0x57

        $sequence_7 = { 8bec 83ec0c c745f400000000 6a00 6880000000 6a03 }
            // n = 6, score = 500
            //   8bec                 | mov                 ebp, esp
            //   83ec0c               | sub                 esp, 0xc
            //   c745f400000000       | mov                 dword ptr [ebp - 0xc], 0
            //   6a00                 | push                0
            //   6880000000           | push                0x80
            //   6a03                 | push                3

        $sequence_8 = { 8a481e 884a03 8b5508 8b4508 8a4815 884a1e }
            // n = 6, score = 500
            //   8a481e               | mov                 cl, byte ptr [eax + 0x1e]
            //   884a03               | mov                 byte ptr [edx + 3], cl
            //   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_9 = { 0355f8 8a8294010000 8801 ebd3 }
            // n = 4, score = 500
            //   0355f8               | add                 edx, dword ptr [ebp - 8]
            //   8a8294010000         | mov                 al, byte ptr [edx + 0x194]
            //   8801                 | mov                 byte ptr [ecx], al
            //   ebd3                 | jmp                 0xffffffd5

        $sequence_10 = { 8b4df8 51 e8???????? 83c404 8945fc 6a00 }
            // n = 6, score = 500
            //   8b4df8               | mov                 ecx, dword ptr [ebp - 8]
            //   51                   | push                ecx
            //   e8????????           |                     
            //   83c404               | add                 esp, 4
            //   8945fc               | mov                 dword ptr [ebp - 4], eax
            //   6a00                 | push                0

        $sequence_11 = { ff15???????? 33c0 e9???????? e8???????? 85c0 7507 }
            // n = 6, score = 400
            //   ff15????????         |                     
            //   33c0                 | xor                 eax, eax
            //   e9????????           |                     
            //   e8????????           |                     
            //   85c0                 | test                eax, eax
            //   7507                 | jne                 9

        $sequence_12 = { e8???????? c78424c002000001000000 488b8c2400030000 e8???????? }
            // n = 4, score = 200
            //   e8????????           |                     
            //   c78424c002000001000000     | mov    ecx, dword ptr [esp + 0x290]
            //   488b8c2400030000     | dec                 eax
            //   e8????????           |                     

        $sequence_13 = { e8???????? c78424a003000000000000 8b8c2490020000 ff15???????? 488d9424a0030000 }
            // n = 5, score = 200
            //   e8????????           |                     
            //   c78424a003000000000000     | mov    dword ptr [esp + 0x3a0], 0
            //   8b8c2490020000       | mov                 ecx, dword ptr [esp + 0x290]
            //   ff15????????         |                     
            //   488d9424a0030000     | dec                 eax

        $sequence_14 = { e8???????? c78424d404000000000000 488d8424d4040000 4889442428 }
            // n = 4, score = 200
            //   e8????????           |                     
            //   c78424d404000000000000     | mov    dword ptr [esp + 0x4fc], 1
            //   488d8424d4040000     | mov                 dword ptr [esp + 0x4c0], 0x68
            //   4889442428           | xor                 eax, eax

        $sequence_15 = { e8???????? c78424c004000068000000 33c0 6689842400050000 }
            // n = 4, score = 200
            //   e8????????           |                     
            //   c78424c004000068000000     | mov    ecx, dword ptr [esp + 0x300]
            //   33c0                 | mov                 eax, dword ptr [esp + 0x2c0]
            //   6689842400050000     | dec                 eax

    condition:
        7 of them and filesize < 2031616
}