rule win_vidar_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2021-06-10"
        version = "1"
        description = "Detects win.vidar."
        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.vidar"
        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 = { c20400 ff742408 e8???????? 59 83f8ff 7503 32c0 }
            // n = 7, score = 1700
            //   c20400               | ret                 4
            //   ff742408             | push                dword ptr [esp + 8]
            //   e8????????           |                     
            //   59                   | pop                 ecx
            //   83f8ff               | cmp                 eax, -1
            //   7503                 | jne                 5
            //   32c0                 | xor                 al, al

        $sequence_1 = { 83f8ff 7503 32c0 c3 8b4c2404 8801 b001 }
            // n = 7, score = 1700
            //   83f8ff               | cmp                 eax, -1
            //   7503                 | jne                 5
            //   32c0                 | xor                 al, al
            //   c3                   | ret                 
            //   8b4c2404             | mov                 ecx, dword ptr [esp + 4]
            //   8801                 | mov                 byte ptr [ecx], al
            //   b001                 | mov                 al, 1

        $sequence_2 = { c9 c3 8b542408 85d2 7503 }
            // n = 5, score = 1700
            //   c9                   | leave               
            //   c3                   | ret                 
            //   8b542408             | mov                 edx, dword ptr [esp + 8]
            //   85d2                 | test                edx, edx
            //   7503                 | jne                 5

        $sequence_3 = { 8910 8b4130 8910 c3 56 }
            // n = 5, score = 1700
            //   8910                 | mov                 dword ptr [eax], edx
            //   8b4130               | mov                 eax, dword ptr [ecx + 0x30]
            //   8910                 | mov                 dword ptr [eax], edx
            //   c3                   | ret                 
            //   56                   | push                esi

        $sequence_4 = { c20400 56 8bf1 8b4e20 33c0 3901 7405 }
            // n = 7, score = 1700
            //   c20400               | ret                 4
            //   56                   | push                esi
            //   8bf1                 | mov                 esi, ecx
            //   8b4e20               | mov                 ecx, dword ptr [esi + 0x20]
            //   33c0                 | xor                 eax, eax
            //   3901                 | cmp                 dword ptr [ecx], eax
            //   7405                 | je                  7

        $sequence_5 = { c20400 56 8bf1 e8???????? 6a00 ff74240c 8bce }
            // n = 7, score = 1700
            //   c20400               | ret                 4
            //   56                   | push                esi
            //   8bf1                 | mov                 esi, ecx
            //   e8????????           |                     
            //   6a00                 | push                0
            //   ff74240c             | push                dword ptr [esp + 0xc]
            //   8bce                 | mov                 ecx, esi

        $sequence_6 = { c3 56 8d71f8 8bce }
            // n = 4, score = 1700
            //   c3                   | ret                 
            //   56                   | push                esi
            //   8d71f8               | lea                 esi, dword ptr [ecx - 8]
            //   8bce                 | mov                 ecx, esi

        $sequence_7 = { c20800 56 57 8b7c240c 8b07 8bf1 }
            // n = 6, score = 1700
            //   c20800               | ret                 8
            //   56                   | push                esi
            //   57                   | push                edi
            //   8b7c240c             | mov                 edi, dword ptr [esp + 0xc]
            //   8b07                 | mov                 eax, dword ptr [edi]
            //   8bf1                 | mov                 esi, ecx

        $sequence_8 = { c3 8bff 55 8bec 83ec0c c745fc00000000 }
            // n = 6, score = 200
            //   c3                   | ret                 
            //   8bff                 | mov                 edi, edi
            //   55                   | push                ebp
            //   8bec                 | mov                 ebp, esp
            //   83ec0c               | sub                 esp, 0xc
            //   c745fc00000000       | mov                 dword ptr [ebp - 4], 0

        $sequence_9 = { dd1c24 83ec08 dd4508 dd1c24 6a0b 6a10 e8???????? }
            // n = 7, score = 200
            //   dd1c24               | fstp                qword ptr [esp]
            //   83ec08               | sub                 esp, 8
            //   dd4508               | fld                 qword ptr [ebp + 8]
            //   dd1c24               | fstp                qword ptr [esp]
            //   6a0b                 | push                0xb
            //   6a10                 | push                0x10
            //   e8????????           |                     

        $sequence_10 = { dd4508 dd1c24 6a0b 6a08 e8???????? 83c41c }
            // n = 6, score = 200
            //   dd4508               | fld                 qword ptr [ebp + 8]
            //   dd1c24               | fstp                qword ptr [esp]
            //   6a0b                 | push                0xb
            //   6a08                 | push                8
            //   e8????????           |                     
            //   83c41c               | add                 esp, 0x1c

        $sequence_11 = { 0006 4a 42 0032 }
            // n = 4, score = 100
            //   0006                 | add                 byte ptr [esi], al
            //   4a                   | dec                 edx
            //   42                   | inc                 edx
            //   0032                 | add                 byte ptr [edx], dh

        $sequence_12 = { 000d???????? 45 43 001f }
            // n = 4, score = 100
            //   000d????????         |                     
            //   45                   | inc                 ebp
            //   43                   | inc                 ebx
            //   001f                 | add                 byte ptr [edi], bl

        $sequence_13 = { 0013 17 43 0020 }
            // n = 4, score = 100
            //   0013                 | add                 byte ptr [ebx], dl
            //   17                   | pop                 ss
            //   43                   | inc                 ebx
            //   0020                 | add                 byte ptr [eax], ah

    condition:
        7 of them and filesize < 2793472
}

rule win_vidar_w0 {
    meta:
        description = "Yara rule for detecting Vidar stealer"
        author = "Fumik0_"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.vidar"
        malpedia_version = "20190106"
        malpedia_license = "CC BY-NC-SA 4.0"
        malpedia_sharing = "TLP:WHITE"

    strings:
        $s1 = { 56 69 64 61 72 }
        $s2 = { 31 42 45 46 30 41 35 37 42 45 31 31 30 46 44 34 36 37 41 }
        
    condition:
        all of them
}