rule win_tofsee_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2021-06-10"
        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 = "20210604"
        malpedia_hash = "be09d5d71e77373c0f538068be31a2ad4c69cfbd"
        malpedia_version = "20210616"
        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 = { 8b442404 83f801 7504 6a05 58 c3 83f803 }
            // n = 7, score = 400
            //   8b442404             | mov                 eax, dword ptr [esp + 4]
            //   83f801               | cmp                 eax, 1
            //   7504                 | jne                 6
            //   6a05                 | push                5
            //   58                   | pop                 eax
            //   c3                   | ret                 
            //   83f803               | cmp                 eax, 3

        $sequence_1 = { 8b45f4 c1e802 0345f4 3945f8 0f85a2000000 8b45f8 56 }
            // n = 7, score = 400
            //   8b45f4               | mov                 eax, dword ptr [ebp - 0xc]
            //   c1e802               | shr                 eax, 2
            //   0345f4               | add                 eax, dword ptr [ebp - 0xc]
            //   3945f8               | cmp                 dword ptr [ebp - 8], eax
            //   0f85a2000000         | jne                 0xa8
            //   8b45f8               | mov                 eax, dword ptr [ebp - 8]
            //   56                   | push                esi

        $sequence_2 = { 8a08 40 84c9 75f9 2bc2 7412 80bc0583feffff5c }
            // n = 7, score = 400
            //   8a08                 | mov                 cl, byte ptr [eax]
            //   40                   | inc                 eax
            //   84c9                 | test                cl, cl
            //   75f9                 | jne                 0xfffffffb
            //   2bc2                 | sub                 eax, edx
            //   7412                 | je                  0x14
            //   80bc0583feffff5c     | cmp                 byte ptr [ebp + eax - 0x17d], 0x5c

        $sequence_3 = { 395dfc 8d443301 894508 7516 }
            // n = 4, score = 400
            //   395dfc               | cmp                 dword ptr [ebp - 4], ebx
            //   8d443301             | lea                 eax, dword ptr [ebx + esi + 1]
            //   894508               | mov                 dword ptr [ebp + 8], eax
            //   7516                 | jne                 0x18

        $sequence_4 = { 50 ff15???????? 6800010000 53 56 e8???????? 83c40c }
            // n = 7, score = 400
            //   50                   | push                eax
            //   ff15????????         |                     
            //   6800010000           | push                0x100
            //   53                   | push                ebx
            //   56                   | push                esi
            //   e8????????           |                     
            //   83c40c               | add                 esp, 0xc

        $sequence_5 = { a1???????? 8d440601 50 ff742418 e8???????? 8bf8 }
            // n = 6, score = 400
            //   a1????????           |                     
            //   8d440601             | lea                 eax, dword ptr [esi + eax + 1]
            //   50                   | push                eax
            //   ff742418             | push                dword ptr [esp + 0x18]
            //   e8????????           |                     
            //   8bf8                 | mov                 edi, eax

        $sequence_6 = { ff7508 e8???????? 83c41c c9 c3 8b442404 57 }
            // n = 7, score = 400
            //   ff7508               | push                dword ptr [ebp + 8]
            //   e8????????           |                     
            //   83c41c               | add                 esp, 0x1c
            //   c9                   | leave               
            //   c3                   | ret                 
            //   8b442404             | mov                 eax, dword ptr [esp + 4]
            //   57                   | push                edi

        $sequence_7 = { 8bd6 d3fa 83e201 52 ffd0 85c0 }
            // n = 6, score = 400
            //   8bd6                 | mov                 edx, esi
            //   d3fa                 | sar                 edx, cl
            //   83e201               | and                 edx, 1
            //   52                   | push                edx
            //   ffd0                 | call                eax
            //   85c0                 | test                eax, eax

        $sequence_8 = { 56 e8???????? 83c414 50 ff742428 ff15???????? ff742414 }
            // n = 7, score = 400
            //   56                   | push                esi
            //   e8????????           |                     
            //   83c414               | add                 esp, 0x14
            //   50                   | push                eax
            //   ff742428             | push                dword ptr [esp + 0x28]
            //   ff15????????         |                     
            //   ff742414             | push                dword ptr [esp + 0x14]

        $sequence_9 = { 0345fc 8a4d0c 8808 ebe4 8b4508 c9 c3 }
            // n = 7, score = 400
            //   0345fc               | add                 eax, dword ptr [ebp - 4]
            //   8a4d0c               | mov                 cl, byte ptr [ebp + 0xc]
            //   8808                 | mov                 byte ptr [eax], cl
            //   ebe4                 | jmp                 0xffffffe6
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   c9                   | leave               
            //   c3                   | ret                 

    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))
}