rule win_vidar_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2020-08-17"
        version = "1"
        description = "autogenerated rule brought to you by yara-signator"
        tool = "yara-signator v0.4.0"
        tool_config = "callsandjumps;datarefs;binvalue"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.vidar"
        malpedia_rule_date = "20200817"
        malpedia_hash = "8c895fd01eccb47a6225bcb1a3ba53cbb98644c5"
        malpedia_version = "20200817"
        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 / approach 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 = { 5e c20400 ff742408 e8???????? 59 }
            // n = 5, score = 1000
            //   5e                   | pop                 esi
            //   c20400               | ret                 4
            //   ff742408             | push                dword ptr [esp + 8]
            //   e8????????           |                     
            //   59                   | pop                 ecx

        $sequence_1 = { c20800 56 57 8b7c240c 8b07 8bf1 8bcf }
            // n = 7, score = 1000
            //   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
            //   8bcf                 | mov                 ecx, edi

        $sequence_2 = { 0fb6c0 50 ff742410 56 e8???????? }
            // n = 5, score = 1000
            //   0fb6c0               | movzx               eax, al
            //   50                   | push                eax
            //   ff742410             | push                dword ptr [esp + 0x10]
            //   56                   | push                esi
            //   e8????????           |                     

        $sequence_3 = { c3 56 8d71f8 8bce }
            // n = 4, score = 1000
            //   c3                   | ret                 
            //   56                   | push                esi
            //   8d71f8               | lea                 esi, [ecx - 8]
            //   8bce                 | mov                 ecx, esi

        $sequence_4 = { 59 83f8ff 7503 32c0 c3 8b4c2404 }
            // n = 6, score = 1000
            //   59                   | pop                 ecx
            //   83f8ff               | cmp                 eax, -1
            //   7503                 | jne                 5
            //   32c0                 | xor                 al, al
            //   c3                   | ret                 
            //   8b4c2404             | mov                 ecx, dword ptr [esp + 4]

        $sequence_5 = { c20400 56 8bf1 e8???????? 6a00 ff74240c 8bce }
            // n = 7, score = 1000
            //   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 = { c9 c3 8b542408 85d2 7503 33c0 }
            // n = 6, score = 1000
            //   c9                   | leave               
            //   c3                   | ret                 
            //   8b542408             | mov                 edx, dword ptr [esp + 8]
            //   85d2                 | test                edx, edx
            //   7503                 | jne                 5
            //   33c0                 | xor                 eax, eax

        $sequence_7 = { 56 8b742408 8b06 8b4804 6a0a 03ce }
            // n = 6, score = 1000
            //   56                   | push                esi
            //   8b742408             | mov                 esi, dword ptr [esp + 8]
            //   8b06                 | mov                 eax, dword ptr [esi]
            //   8b4804               | mov                 ecx, dword ptr [eax + 4]
            //   6a0a                 | push                0xa
            //   03ce                 | add                 ecx, esi

        $sequence_8 = { 83ec08 dd4508 dd1c24 6a0b 6a08 e8???????? }
            // n = 6, score = 200
            //   83ec08               | sub                 esp, 8
            //   dd4508               | fld                 qword ptr [ebp + 8]
            //   dd1c24               | fstp                qword ptr [esp]
            //   6a0b                 | push                0xb
            //   6a08                 | push                8
            //   e8????????           |                     

        $sequence_9 = { 6a0b 6a10 e8???????? 83c41c 8be5 }
            // n = 5, score = 200
            //   6a0b                 | push                0xb
            //   6a10                 | push                0x10
            //   e8????????           |                     
            //   83c41c               | add                 esp, 0x1c
            //   8be5                 | mov                 esp, ebp

        $sequence_10 = { e8???????? ff35???????? a3???????? ff15???????? }
            // n = 4, score = 200
            //   e8????????           |                     
            //   ff35????????         |                     
            //   a3????????           |                     
            //   ff15????????         |                     

        $sequence_11 = { 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_12 = { 51 57 8bf9 8d4c2404 6a03 e8???????? }
            // n = 6, score = 100
            //   51                   | push                ecx
            //   57                   | push                edi
            //   8bf9                 | mov                 edi, ecx
            //   8d4c2404             | lea                 ecx, [esp + 4]
            //   6a03                 | push                3
            //   e8????????           |                     

        $sequence_13 = { 8b442454 8b4004 8b8c048c000000 85c9 7405 8b01 }
            // n = 6, score = 100
            //   8b442454             | mov                 eax, dword ptr [esp + 0x54]
            //   8b4004               | mov                 eax, dword ptr [eax + 4]
            //   8b8c048c000000       | mov                 ecx, dword ptr [esp + eax + 0x8c]
            //   85c9                 | test                ecx, ecx
            //   7405                 | je                  7
            //   8b01                 | mov                 eax, dword ptr [ecx]

        $sequence_14 = { 8b55f0 52 ff15???????? 8945e0 837dec00 7451 837de400 }
            // n = 7, score = 100
            //   8b55f0               | mov                 edx, dword ptr [ebp - 0x10]
            //   52                   | push                edx
            //   ff15????????         |                     
            //   8945e0               | mov                 dword ptr [ebp - 0x20], eax
            //   837dec00             | cmp                 dword ptr [ebp - 0x14], 0
            //   7451                 | je                  0x53
            //   837de400             | cmp                 dword ptr [ebp - 0x1c], 0

    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
}