rule win_tofsee_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2020-10-14"
        version = "1"
        description = "autogenerated rule brought to you by yara-signator"
        tool = "yara-signator v0.5.0"
        tool_config = "callsandjumps;datarefs;binvalue"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.tofsee"
        malpedia_rule_date = "20201014"
        malpedia_hash = "a7e3bd57eaf12bf3ea29a863c041091ba3af9ac9"
        malpedia_version = "20201014"
        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 = { 5f 5e 5b c9 c3 891d???????? }
            // n = 6, score = 400
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi
            //   5b                   | pop                 ebx
            //   c9                   | leave               
            //   c3                   | ret                 
            //   891d????????         |                     

        $sequence_1 = { 59 894e08 ff4710 8b4710 3b4714 7c1b 894f08 }
            // n = 7, score = 400
            //   59                   | pop                 ecx
            //   894e08               | mov                 dword ptr [esi + 8], ecx
            //   ff4710               | inc                 dword ptr [edi + 0x10]
            //   8b4710               | mov                 eax, dword ptr [edi + 0x10]
            //   3b4714               | cmp                 eax, dword ptr [edi + 0x14]
            //   7c1b                 | jl                  0x1d
            //   894f08               | mov                 dword ptr [edi + 8], ecx

        $sequence_2 = { 50 57 56 6a0c 68???????? 53 e8???????? }
            // n = 7, score = 400
            //   50                   | push                eax
            //   57                   | push                edi
            //   56                   | push                esi
            //   6a0c                 | push                0xc
            //   68????????           |                     
            //   53                   | push                ebx
            //   e8????????           |                     

        $sequence_3 = { eb08 8a1c30 881c11 41 40 3b4510 7cf3 }
            // n = 7, score = 400
            //   eb08                 | jmp                 0xa
            //   8a1c30               | mov                 bl, byte ptr [eax + esi]
            //   881c11               | mov                 byte ptr [ecx + edx], bl
            //   41                   | inc                 ecx
            //   40                   | inc                 eax
            //   3b4510               | cmp                 eax, dword ptr [ebp + 0x10]
            //   7cf3                 | jl                  0xfffffff5

        $sequence_4 = { 75e4 5f 5e 5d 5b c3 83610400 }
            // n = 7, score = 400
            //   75e4                 | jne                 0xffffffe6
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi
            //   5d                   | pop                 ebp
            //   5b                   | pop                 ebx
            //   c3                   | ret                 
            //   83610400             | and                 dword ptr [ecx + 4], 0

        $sequence_5 = { 85c9 7e24 0fbec0 89442410 55 0fbe0437 6bdb1a }
            // n = 7, score = 400
            //   85c9                 | test                ecx, ecx
            //   7e24                 | jle                 0x26
            //   0fbec0               | movsx               eax, al
            //   89442410             | mov                 dword ptr [esp + 0x10], eax
            //   55                   | push                ebp
            //   0fbe0437             | movsx               eax, byte ptr [edi + esi]
            //   6bdb1a               | imul                ebx, ebx, 0x1a

        $sequence_6 = { 8bc2 03c6 eb02 8bc6 5b 5e 5f }
            // n = 7, score = 400
            //   8bc2                 | mov                 eax, edx
            //   03c6                 | add                 eax, esi
            //   eb02                 | jmp                 4
            //   8bc6                 | mov                 eax, esi
            //   5b                   | pop                 ebx
            //   5e                   | pop                 esi
            //   5f                   | pop                 edi

        $sequence_7 = { 33ff ff7510 53 eb1b 3d46270000 741d 03f8 }
            // n = 7, score = 400
            //   33ff                 | xor                 edi, edi
            //   ff7510               | push                dword ptr [ebp + 0x10]
            //   53                   | push                ebx
            //   eb1b                 | jmp                 0x1d
            //   3d46270000           | cmp                 eax, 0x2746
            //   741d                 | je                  0x1f
            //   03f8                 | add                 edi, eax

        $sequence_8 = { 0fb70433 8b3d???????? 50 ffd7 43 668945e0 }
            // n = 6, score = 400
            //   0fb70433             | movzx               eax, word ptr [ebx + esi]
            //   8b3d????????         |                     
            //   50                   | push                eax
            //   ffd7                 | call                edi
            //   43                   | inc                 ebx
            //   668945e0             | mov                 word ptr [ebp - 0x20], ax

        $sequence_9 = { 53 56 68???????? 33db e8???????? 8b35???????? 81fe???????? }
            // n = 7, score = 400
            //   53                   | push                ebx
            //   56                   | push                esi
            //   68????????           |                     
            //   33db                 | xor                 ebx, ebx
            //   e8????????           |                     
            //   8b35????????         |                     
            //   81fe????????         |                     

    condition:
        7 of them and filesize < 147456
}

rule win_tofsee_w0 {
    meta:
        author="akrasuski1"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.tofsee"
        malpedia_version = "20171121"
        malpedia_license = "CC BY-NC-SA 4.0"
        malpedia_sharing = "TLP:WHITE"
    strings:

        $decryptStr = {32 55 14 88 10 8A D1 02 55 18 F6 D9 00 55 14}
        $xorGreet = {C1 EB 03 C0 E1 05 0A D9 32 DA 34 C6 88 1E}
        $xorCrypt = {F7 FB 8A 44 0A 04 30 06 FF 41 0C}

        $string_res1 = "loader_id"
        $string_res2 = "born_date"
        $string_res3 = "work_srv"
        $string_res4 = "flags_upd"
        $string_res5 = "lid_file_upd"
        $string_res6 = "localcfg"

        $string_var0 = "%RND_NUM"
        $string_var1 = "%SYS_JR"
        $string_var2 = "%SYS_N"
        $string_var3 = "%SYS_RN"
        $string_var4 = "%RND_SPACE"
        $string_var5 = "%RND_DIGIT"
        $string_var6 = "%RND_HEX"
        $string_var7 = "%RND_hex"
        $string_var8 = "%RND_char"
        $string_var9 = "%RND_CHAR"

    condition:
        (7 of ($string_var*) and 4 of ($string_res*))
        or
        (7 of ($string_var*) and 2 of ($decryptStr, $xorGreet, $xorCrypt))
        or
        (4 of ($string_res*) and 2 of ($decryptStr, $xorGreet, $xorCrypt))
}