rule win_tofsee_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2023-03-28"
        version = "1"
        description = "Detects win.tofsee."
        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.tofsee"
        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 = { 46 84c0 75f9 2bf1 f60304 7474 e8???????? }
            // n = 7, score = 400
            //   46                   | inc                 esi
            //   84c0                 | test                al, al
            //   75f9                 | jne                 0xfffffffb
            //   2bf1                 | sub                 esi, ecx
            //   f60304               | test                byte ptr [ebx], 4
            //   7474                 | je                  0x76
            //   e8????????           |                     

        $sequence_1 = { eb0a c705????????2c010000 53 e8???????? 2b05???????? 59 3bc5 }
            // n = 7, score = 400
            //   eb0a                 | jmp                 0xc
            //   c705????????2c010000     |     
            //   53                   | push                ebx
            //   e8????????           |                     
            //   2b05????????         |                     
            //   59                   | pop                 ecx
            //   3bc5                 | cmp                 eax, ebp

        $sequence_2 = { 41 85c0 88540ddb 75f0 8b750c 8bc1 49 }
            // n = 7, score = 400
            //   41                   | inc                 ecx
            //   85c0                 | test                eax, eax
            //   88540ddb             | mov                 byte ptr [ebp + ecx - 0x25], dl
            //   75f0                 | jne                 0xfffffff2
            //   8b750c               | mov                 esi, dword ptr [ebp + 0xc]
            //   8bc1                 | mov                 eax, ecx
            //   49                   | dec                 ecx

        $sequence_3 = { 83c8ff c3 1bc0 f7d8 c3 8b4c2408 }
            // n = 6, score = 400
            //   83c8ff               | or                  eax, 0xffffffff
            //   c3                   | ret                 
            //   1bc0                 | sbb                 eax, eax
            //   f7d8                 | neg                 eax
            //   c3                   | ret                 
            //   8b4c2408             | mov                 ecx, dword ptr [esp + 8]

        $sequence_4 = { 66895806 a1???????? 66895808 a1???????? 6689580a 8b15???????? }
            // n = 6, score = 400
            //   66895806             | mov                 word ptr [eax + 6], bx
            //   a1????????           |                     
            //   66895808             | mov                 word ptr [eax + 8], bx
            //   a1????????           |                     
            //   6689580a             | mov                 word ptr [eax + 0xa], bx
            //   8b15????????         |                     

        $sequence_5 = { 837d0c03 7510 80781000 0f8434020000 56 e9???????? 8b4f14 }
            // n = 7, score = 400
            //   837d0c03             | cmp                 dword ptr [ebp + 0xc], 3
            //   7510                 | jne                 0x12
            //   80781000             | cmp                 byte ptr [eax + 0x10], 0
            //   0f8434020000         | je                  0x23a
            //   56                   | push                esi
            //   e9????????           |                     
            //   8b4f14               | mov                 ecx, dword ptr [edi + 0x14]

        $sequence_6 = { eb04 834e1401 ffd7 a3???????? ffd7 bde8030000 33d2 }
            // n = 7, score = 400
            //   eb04                 | jmp                 6
            //   834e1401             | or                  dword ptr [esi + 0x14], 1
            //   ffd7                 | call                edi
            //   a3????????           |                     
            //   ffd7                 | call                edi
            //   bde8030000           | mov                 ebp, 0x3e8
            //   33d2                 | xor                 edx, edx

        $sequence_7 = { 5d f7fd 03da 47 3bf9 7ce5 5d }
            // n = 7, score = 400
            //   5d                   | pop                 ebp
            //   f7fd                 | idiv                ebp
            //   03da                 | add                 ebx, edx
            //   47                   | inc                 edi
            //   3bf9                 | cmp                 edi, ecx
            //   7ce5                 | jl                  0xffffffe7
            //   5d                   | pop                 ebp

        $sequence_8 = { 50 ff15???????? ff742424 ff15???????? 8b442418 eb0d }
            // n = 6, score = 400
            //   50                   | push                eax
            //   ff15????????         |                     
            //   ff742424             | push                dword ptr [esp + 0x24]
            //   ff15????????         |                     
            //   8b442418             | mov                 eax, dword ptr [esp + 0x18]
            //   eb0d                 | jmp                 0xf

        $sequence_9 = { 7428 8b00 85c0 7413 8b10 6a01 8bc8 }
            // n = 7, score = 400
            //   7428                 | je                  0x2a
            //   8b00                 | mov                 eax, dword ptr [eax]
            //   85c0                 | test                eax, eax
            //   7413                 | je                  0x15
            //   8b10                 | mov                 edx, dword ptr [eax]
            //   6a01                 | push                1
            //   8bc8                 | mov                 ecx, eax

    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))
}