win.extreme_rat (Back to overview)

Xtreme RAT

aka: ExtRat

Actor(s): Molerats

URLhaus      

There is no description at this point.

References
https://www.fireeye.com/blog/threat-research/2014/02/xtremerat-nuisance-or-threat.html
https://malware.lu/articles/2012/07/22/xtreme-rat-analysis.html
https://community.rsa.com/community/products/netwitness/blog/2017/08/02/malspam-delivers-xtreme-rat-8-1-2017
https://www.symantec.com/connect/blogs/colombians-major-target-email-campaigns-delivering-xtreme-rat
Yara Rules
[TLP:WHITE] win_extreme_rat_auto (20180607 | autogenerated rule brought to you by yara-signator)
rule win_extreme_rat_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2018-11-23"
        version = "1"
        description = "autogenerated rule brought to you by yara-signator"
        tool = "yara-signator 0.1a"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.extreme_rat"
        malpedia_version = "20180607"
        malpedia_license = "CC BY-NC-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 will be published in the near future 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 = { 83e000 50 a190b5c800 50 }
            // n = 4, score = 3000
            //   83e000               | and                 eax, 0
            //   50                   | push                eax
            //   a190b5c800           | mov                 eax, dword ptr [0xc8b590]
            //   50                   | push                eax

        $sequence_1 = { 50 6a00 8b55f4 8b4de0 }
            // n = 4, score = 3000
            //   50                   | push                eax
            //   6a00                 | push                0
            //   8b55f4               | mov                 edx, dword ptr [ebp - 0xc]
            //   8b4de0               | mov                 ecx, dword ptr [ebp - 0x20]

        $sequence_2 = { 8a1a 3a1e 7404 33c9 }
            // n = 4, score = 3000
            //   8a1a                 | mov                 bl, byte ptr [edx]
            //   3a1e                 | cmp                 bl, byte ptr [esi]
            //   7404                 | je                  0xc8367b
            //   33c9                 | xor                 ecx, ecx

        $sequence_3 = { 8d45e8 50 e801feffff 0fb745f0 }
            // n = 4, score = 3000
            //   8d45e8               | lea                 eax, dword ptr [ebp - 0x18]
            //   50                   | push                eax
            //   e801feffff           | call                0xc81058
            //   0fb745f0             | movzx               eax, word ptr [ebp - 0x10]

        $sequence_4 = { 668b03 6683f820 7797 8bc3 }
            // n = 4, score = 3000
            //   668b03               | mov                 ax, word ptr [ebx]
            //   6683f820             | cmp                 ax, 0x20
            //   7797                 | ja                  0xc83036
            //   8bc3                 | mov                 eax, ebx

        $sequence_5 = { 8bd8 33c0 a378a0c800 6a00 }
            // n = 4, score = 3000
            //   8bd8                 | mov                 ebx, eax
            //   33c0                 | xor                 eax, eax
            //   a378a0c800           | mov                 dword ptr [0xc8a078], eax
            //   6a00                 | push                0

        $sequence_6 = { 8d1447 66c7020000 40 83c202 }
            // n = 4, score = 3000
            //   8d1447               | lea                 edx, dword ptr [edi + eax*2]
            //   66c7020000           | mov                 word ptr [edx], 0
            //   40                   | inc                 eax
            //   83c202               | add                 edx, 2

        $sequence_7 = { 837df800 0f864a010000 8b45f4 e83fffffff }
            // n = 4, score = 3000
            //   837df800             | cmp                 dword ptr [ebp - 8], 0
            //   0f864a010000         | jbe                 0xc82aa3
            //   8b45f4               | mov                 eax, dword ptr [ebp - 0xc]
            //   e83fffffff           | call                0xc828a0

        $sequence_8 = { 64ff32 648922 8d8534feffff 33c9 }
            // n = 4, score = 3000
            //   64ff32               | push                dword ptr fs:[edx]
            //   648922               | mov                 dword ptr fs:[edx], esp
            //   8d8534feffff         | lea                 eax, dword ptr [ebp - 0x1cc]
            //   33c9                 | xor                 ecx, ecx

        $sequence_9 = { 84c0 754a 6880000000 57 }
            // n = 4, score = 3000
            //   84c0                 | test                al, al
            //   754a                 | jne                 0xc890dc
            //   6880000000           | push                0x80
            //   57                   | push                edi

    condition:
        7 of them
}
[TLP:WHITE] win_extreme_rat_w0   (20170517 | Xtrem RAT v3.5)
rule win_extreme_rat_w0 {
	meta:
		author = "Jean-Philippe Teissier / @Jipe_"
		description = "Xtrem RAT v3.5"
		date = "2012-07-12" 
		version = "1.0" 
		filetype = "memory"
		source = "https://github.com/mattulm/sfiles_yara/blob/master/malware/xTremRat.yar"
        malpedia_version = "20170517"
        malpedia_license = "CC BY-NC-SA 4.0"
        malpedia_sharing = "TLP:WHITE"

	strings:
		$a = "XTREME" wide
		$b = "XTREMEBINDER" wide
		$c = "STARTSERVERBUFFER" wide
		$d = "SOFTWARE\\XtremeRAT" wide
		$e = "XTREMEUPDATE" wide
		$f = "XtremeKeylogger" wide
		$g = "myversion|3.5" wide
		$h = "xtreme rat" wide nocase
	condition:
		2 of them
}
[TLP:WHITE] win_extreme_rat_w1   (20170517 | XtremeRAT)
rule win_extreme_rat_w1 {
    meta:
        description = "XtremeRAT"
        author = "Seth Hardy <seth.hardy@utoronto.ca>"
        last_modified = "2014-07-09"
		source = "https://github.com/mattulm/sfiles_yara/blob/master/malware/xTremRat.yar"
        malpedia_version = "20170517"
        malpedia_license = "CC BY-NC-SA 4.0"
        malpedia_sharing = "TLP:WHITE"
    
    strings:
        // call; fstp st
        $code1 = { E8 ?? ?? ?? ?? DD D8 }
        // hiding string
        $code2 = { C6 85 ?? ?? ?? ?? 4D C6 85 ?? ?? ?? ?? 70 C6 85 ?? ?? ?? ?? 64 C6 85 ?? ?? ?? ?? 62 C6 85 ?? ?? ?? ?? 6D }
        $str1 = "dqsaazere"
        $str2 = "-GCCLIBCYGMING-EH-TDM1-SJLJ-GTHR-MINGW32"
        
    condition:
       all of ($code*) or any of ($str*)
}
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