rule win_darkrat_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2024-10-31"
        version = "1"
        description = "Detects win.darkrat."
        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.darkrat"
        malpedia_rule_date = "20241030"
        malpedia_hash = "26e26953c49c8efafbf72a38076855d578e0a2e4"
        malpedia_version = "20241030"
        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 = { 8b75b8 8b4314 0f43d6 8b7b10 2bc7 8b4dc8 }
            // n = 6, score = 200
            //   8b75b8               | mov                 esi, dword ptr [ebp - 0x48]
            //   8b4314               | mov                 eax, dword ptr [ebx + 0x14]
            //   0f43d6               | cmovae              edx, esi
            //   8b7b10               | mov                 edi, dword ptr [ebx + 0x10]
            //   2bc7                 | sub                 eax, edi
            //   8b4dc8               | mov                 ecx, dword ptr [ebp - 0x38]

        $sequence_1 = { 85c0 7446 8bd0 b805000000 2bd6 8a0e 8d7601 }
            // n = 7, score = 200
            //   85c0                 | test                eax, eax
            //   7446                 | je                  0x48
            //   8bd0                 | mov                 edx, eax
            //   b805000000           | mov                 eax, 5
            //   2bd6                 | sub                 edx, esi
            //   8a0e                 | mov                 cl, byte ptr [esi]
            //   8d7601               | lea                 esi, [esi + 1]

        $sequence_2 = { 83f801 751f 6a0a 68???????? 8bcb e8???????? }
            // n = 6, score = 200
            //   83f801               | cmp                 eax, 1
            //   751f                 | jne                 0x21
            //   6a0a                 | push                0xa
            //   68????????           |                     
            //   8bcb                 | mov                 ecx, ebx
            //   e8????????           |                     

        $sequence_3 = { 3bf2 0f8211010000 2bf2 8d45d8 b901000000 3bf1 0f42ce }
            // n = 7, score = 200
            //   3bf2                 | cmp                 esi, edx
            //   0f8211010000         | jb                  0x117
            //   2bf2                 | sub                 esi, edx
            //   8d45d8               | lea                 eax, [ebp - 0x28]
            //   b901000000           | mov                 ecx, 1
            //   3bf1                 | cmp                 esi, ecx
            //   0f42ce               | cmovb               ecx, esi

        $sequence_4 = { 85c0 7413 8b4904 8b00 8b4c3938 }
            // n = 5, score = 200
            //   85c0                 | test                eax, eax
            //   7413                 | je                  0x15
            //   8b4904               | mov                 ecx, dword ptr [ecx + 4]
            //   8b00                 | mov                 eax, dword ptr [eax]
            //   8b4c3938             | mov                 ecx, dword ptr [ecx + edi + 0x38]

        $sequence_5 = { ff15???????? 85c0 7445 8bc6 }
            // n = 4, score = 200
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   7445                 | je                  0x47
            //   8bc6                 | mov                 eax, esi

        $sequence_6 = { 57 50 8975fc e8???????? 8bd0 }
            // n = 5, score = 200
            //   57                   | push                edi
            //   50                   | push                eax
            //   8975fc               | mov                 dword ptr [ebp - 4], esi
            //   e8????????           |                     
            //   8bd0                 | mov                 edx, eax

        $sequence_7 = { e8???????? 8b551c 83fa10 72bd 8b4d08 42 8bc1 }
            // n = 7, score = 200
            //   e8????????           |                     
            //   8b551c               | mov                 edx, dword ptr [ebp + 0x1c]
            //   83fa10               | cmp                 edx, 0x10
            //   72bd                 | jb                  0xffffffbf
            //   8b4d08               | mov                 ecx, dword ptr [ebp + 8]
            //   42                   | inc                 edx
            //   8bc1                 | mov                 eax, ecx

        $sequence_8 = { 6a00 8945ec ff15???????? 8bd8 85db 7462 }
            // n = 6, score = 200
            //   6a00                 | push                0
            //   8945ec               | mov                 dword ptr [ebp - 0x14], eax
            //   ff15????????         |                     
            //   8bd8                 | mov                 ebx, eax
            //   85db                 | test                ebx, ebx
            //   7462                 | je                  0x64

        $sequence_9 = { 8b8d68ffffff 8bc2 2bc1 57 3bf8 7731 8d040f }
            // n = 7, score = 200
            //   8b8d68ffffff         | mov                 ecx, dword ptr [ebp - 0x98]
            //   8bc2                 | mov                 eax, edx
            //   2bc1                 | sub                 eax, ecx
            //   57                   | push                edi
            //   3bf8                 | cmp                 edi, eax
            //   7731                 | ja                  0x33
            //   8d040f               | lea                 eax, [edi + ecx]

    condition:
        7 of them and filesize < 884736
}

rule win_darkrat_w0 {
    meta:
        author = "Albert Zsigovits"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.darkrat"
        malpedia_version = "20191012"
        malpedia_license = "CC BY-SA 4.0"
        malpedia_sharing = "TLP:WHITE"
            
    strings:
	    $pdb = "C:\\Users\\darkspider" ascii wide
	    $cmd = "cmd.exe /C ping 127.0.0.1 -n 1 -w 3000 > Nul & Del /f /q \"%s\"" ascii wide

	    $guid1 = "SOFTWARE\\Microsoft\\Cryptography" ascii wide
	    $guid2 = "MachineGuid" ascii wide

	    $persi1 = "Software\\Microsoft\\Windows\\CurrentVersion\\Run" ascii wide
	    $persi2 = "WinSystem32" ascii wide

	    $bin = "pastebin.com/raw/" ascii wide
	    $import0 = "NtUnmapViewOfSection" ascii wide
	    $import1 = "WriteProcessMemory" ascii wide
	    $import2 = "ResumeThread" ascii wide
	    $import3 = "GetNativeSystemInfo" ascii wide
	    $import4 = "URLOpenBlockingStream" ascii wide
	    $import5 = "VirtualFree" ascii wide
	    $import6 = "VirtualAlloc" ascii wide
	    $import7 = "GetModuleHandle" ascii wide
	    $import8 = "LoadLibrary" ascii wide
	    $import9 = "CreateMutex" ascii wide

	    $vbs0 = "Set objShell = WScript.CreateObject(\"WScript.Shell\")" ascii wide
	    $vbs1 = "Set objWMIService = GetObject(\"winmgmts:\\\\\" & sComputerName & \"\\root\\cimv2\")" ascii wide
	    $vbs2 = "Set objItems = objWMIService.ExecQuery(sQuery)" ascii wide
	    $vbs3 = "sQuery = \"SELECT * FROM Win32_Process\"" ascii wide
	    $vbs4 = "wscript.exe" ascii wide

	    $net0 = "POST" ascii wide
	    $net1 = "&taskid=" ascii wide
	    $net2 = "&taskstatus=" ascii wide
	    $net3 = "&spreadtag=" ascii wide
	    $net4 = "&operingsystem=" ascii wide
	    $net5 = "&arch=" ascii wide
	    $net6 = "&cpuName=" ascii wide
	    $net7 = "&gpuName=" ascii wide
	    $net8 = "&botversion=" ascii wide
	    $net9 = "&antivirus=" ascii wide
	    $net10 = "&netFramework4=" ascii wide
	    $net11 = "&netFramework35=" ascii wide
	    $net12 = "&netFramework3=" ascii wide
	    $net13 = "&netFramework2=" ascii wide
	    $net14 = "&installedRam=" ascii wide
	    $net15 = "&aornot=" ascii wide
	    $net16 = "&computername=" ascii wide
	    $net17 = "hwid=" ascii wide
	    $net18 = "request=" ascii wide

    condition:
	    $pdb or $cmd or ( all of ($guid*) and all of ($persi*) ) or ( 3 of ($vbs*) ) or ( all of ($import*) and $bin ) or ( all of ($net*) )
}

rule win_darkrat_w1 {
    meta:
        description = "Darkrat"
        author = "James_inthe_box"
        reference = "https://github.com/albertzsigovits/malware-writeups/tree/master/DarkRATv2"
        date = "2019/08"
        maltype = "RAT"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.darkrat"
        malpedia_version = "20191012"
        malpedia_license = "CC BY-SA 4.0"
        malpedia_sharing = "TLP:WHITE"
 
    strings:
        $string1 = "Set objShell = WScript.CreateObject(\"WScript.Shell\")"
        $string2 = "&taskstatus="
        $string3 = "network reset"
        $string4 = "text/plain"
        $string5 = "&antivirus="
        $string6 = "request="
        $string7 = "&arch="
 
    condition:
        all of ($string*)
}