Rewterz Threat Advisory – GhostDNS campaign: Trusted binaries abused, DLL Hijacking and Code Injection

A new DNS hijacking campaign called GhostDNS is observed in Brazil, that redirects e-banking customers to phishing webpages.

IMPACT:  MEDIUM

PUBLISH DATE:  22-10-2018

OVERVIEW

A DNS hijacking campaign arising from Brazil with the name GhostDNS was found to be affecting over 100,000 compromised home routers. The campaign aimed to redirect Brazilian e-banking customers to specially crafted phishing web pages.

Security researchers at Cybereason found out that trusted and signed binaries of companies like HP, NVIDIA, RealTek and VMware were also being misused. The attackers hid malicious code in them which was to be loaded by hijacking a DLL. They also went as far as directly injecting it into trusted programs.

ANALYSIS

To operate quietly, attackers are abusing trusted and signed binaries, and are hijacking DLLs, to utilize trusted programs as their “malware launchers”. The PowerShell scripts used for execution in this campaign are identical to those previously associated with Brazilian and Chilean campaigns. Some Portuguese references found in the scripts provide evidence that the attackers have Portuguese links.

A reference in an RTF file to two entries by the name of “Equation.3” indicates that attackers are exploiting a Microsoft Office Memory Corruption Vulnerability in their attacks (CVE-2017-11882).

The vulnerability is one of remote code execution which when exploited lets the attacker run arbitrary code in the context of the current user. This means that an attacker could take control of the affected system and install programs; view, change, or delete data; or create new accounts with full user rights if the current user is logged in with administrative privileges.

A list of threat indicators is available to make sure systems are fully protected against these threat indicators.

THREAT INDICATORS

Following is a list of threat indicators associated with the campaign.

• e0247073e68070413235a8aa92008de2970e1bf0
• 9B6016D9523DE39BF2E5F854549CED9A3F35BE85
• 4F66783ACE879E221C0DB62A92C21FFE587F7B3B
• 5C1AD7C4CD06316172E4AA579C9EB9159C72DBAA
• 08359247B1F9069AA07F015921035F362185D665
• 87358CC245FDF172EC532C2B1C729E1A6F9CB18E
• 9422FAFBC54983EFB10A75A18F039A149F3C1CB2
• 8E12FF6CFC217D5C9A6D1A7487634E50ABEB672E
• 75A29FEC62A95B4C820454CD82DDF70742A67602
• 0EA42E64F4C8653D865EEA79EB3B37B81206CAC1
• 934BF6E81040089253C209A6B4286A235C240473
• 7C5F9C7541FE56FA11703156086D9F9D9C735800
• BBC8628F92209364C79EC38284DC772B81100BD7
• 0EA42E64F4C8653D865EEA79EB3B37B81206CAC1
• 2203714D747145F9363A6F0DE0D5E7F2FEA792AA
• 222D89261CB18D5EB26AC84041BFA0E1B399A2D5
• B77DD8A56F480F052E262ABF9FB856E8B9F8757D
• 363E4734F757BDEB89868EFE94907774A327695E
• Cl[.]ly
• Flashplayers2018[.]com
• Javadownloadbrasil[.]site
• Musicalad[.]com[.]br
• Nfmicrosoft[.]com
• netframework2018-microsoft[.]com
• hxxp://185.135.9[.]102/suspiro/index.php
• hxxp://198.50.138[.]133/latex/index.php
• hxxp://198.50.138[.]131/hilton/index.php
• hxxp://corretorandremendes.com[.]br/images/contA/ponto.php
• hxxp://f.cl[.]ly/items/1k3W1B0G0a3P0O41220g/open.zip
• hxxp://flashplayers2018[.]com/WEBFLASH_IESS.DOC
• hxxp://x.ss2[.]us/x.cer – SSL certificate
• hxxps://cl.ly/390j3n40002a/download/new10[.]zip
• hxxps://cl[.]ly/0a5f7eb35382/download/flatrom.jpg
• hxxps://cl[.]ly/0b2E2g2c3y2L/download/newpepe.png
• hxxps://cl[.]ly/694965a97454/download/xalita.jpg
• hxxps://cl[.]ly/8a89ef6803d6/download/paulo.jpg
• hxxps://cl[.]ly/f6f5fac35d25/download/testepepeu.jpg
• hxxps://s3.amazonaws.com/f.cl[.]ly/items/2y1A3w3I3K12242b0r36/new10.zip?AWSAccessKeyId=AKIAJEFUZRCWSLB2QA5Q&Expires=1531388058&Signature=VDxQ29GFO%2FqanJvH0SZP3yH87CE%3D&response-content-disposition=attachment
• hxxps://supgmx.egnyte[.]com/dd/PPlFR0ONrE/
• 135.9[.]102
• 50.138[.]133
• 50.138[.]131

RECOMMENDATIONS

Organizations may consider to block these threat indicators as per their security rules. However, to avoid impacts on your organization, the IP/Domain blocking requires diligence. Moreover, the attackers seem to be exploiting an old Microsoft Office Memory Corruption Vulnerability (CVE 2017-11882) in order to execute code. Therefore, all users should ensure that this vulnerability is addressed and patched.

Since the phishing techniques are also evolving at an exponential rate, employee training and awareness programs about social engineering and phishing scams should be considered.

If you think you’re the victim of a cyber-attack, immediately send an e-mail to soc@rewterz.com