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This New Malware Hides Itself Among Windows Defender Exclusions to Avoid Detection

 

On Tuesday, security experts confirmed the existence of a previously undocumented malware strain named "MosaicLoader," which targets people looking for cracked software as part of a global campaign. 

Bitdefender researchers stated in a report shared with The Hacker News, "The attackers behind MosaicLoader created a piece of malware that can deliver any payload on the system, making it potentially profitable as a delivery service." 

"The malware arrives on target systems by posing as cracked installers. It downloads a malware sprayer that obtains a list of URLs from the C2 server and downloads the payloads from the received links." 

The malware's name comes from its complex internal structure, which is designed to avoid reverse engineering and escape investigation. MosaicLoader attacks employ a well-known malware delivery technique known as search engine optimization (SEO) poisoning, in which hackers buy ad slots in search engine results to elevate their harmful URLs to the top of the results when users search for keywords linked to pirated software. 

Following a successful infection, the Delphi-based dropper which masquerades as a software installer and serves as an entry point for retrieving next-stage payloads from a remote server and adding local exclusions in Windows Defender for the two downloaded executables in an effort to circumvent antivirus scanning. 

It's important to note that such Windows Defender exclusions can be found in the registry keys listed below: 

1.File and folder exclusions - HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Paths 

2.File type exclusions - HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Extensions 

3.Process exclusions - HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Defender\Exclusions\Processes 

One of the binaries, "appsetup.exe," is designed to attain system persistence, while the second, "prun.exe," is a downloader for a sprayer module that can obtain and deploy a range of attacks from a list of URLs, ranging from cookie stealers to cryptocurrency miners, and even more advanced implants like Glupteba. 

Because of MosaicLoader's broad capabilities, compromised systems can be co-opted into a botnet, which the threat actor can then use to spread a variety of malicious software, including both publicly available and customized malware, to gain, expand, and manage unauthorized access to victim computers and networks. 

The researchers added, "The best way to defend against MosaicLoader is to avoid downloading cracked software from any source."

Besides being against the law, cybercriminals look to target and exploit users searching for illegal software, adding it's essential to check the source domain of every download to make sure that the files are legitimate.

1,500 Businesses Globally were Affected by Kaseya Cyberattack

 

Kaseya, a Miami-based software provider to over 40,000 businesses, reported on July 2 that it was looking into a possible hack. The IT solutions provider for managed service providers (MSPs) and enterprise clients revealed a day later that it had been targeted by a "sophisticated cyberattack." According to CEO Fred Voccola, the ransomware attack has hit between 800 and 1,500 organizations throughout the world. In an interview with Reuters, he said it was impossible to determine the exact impact of the hack because the firms affected were Kaseya's clients. 

REvil, a hacking organization linked to Russia, published a blog on the dark web on Sunday claiming its involvement in the attack. REvil sought $70 million for the data to be restored. REvil has become one of the most well-known ransomware creators in the world. In the last month, it demanded an $11 million payment from the U.S. subsidiary of the world's largest meatpacking company, a $5 million payment from a Brazilian medical diagnostics company, and launched a large-scale attack on dozens, if not hundreds, of companies that use IT management software from Kaseya VSA. 

Kaseya is a company that provides its comprehensive integrated IT management platform to other businesses. It also provides organizations with tools such as VSA (Virtual System/Server Administrator) and other remote monitoring and management solutions for network endpoints. Kaseya also offers compliance systems, service desks, and a platform for service automation. 

According to the FBI, a vulnerability in Kaseya VSA software was used against many MSPs and their clients in the recent supply-chain ransomware campaign. VSA allows a company to control servers and other hardware, as well as software and services, from a remote location. Large enterprises and service providers who manage system administration for companies without their own IT staff utilize the software. 

According to Kevin Beaumont, a security specialist, the REvil ransomware was distributed through an apparent automatic bogus software update in the product. Because the malware had administrator access down to client systems, the MSPs who were attacked were able to infect the systems of their clients.

The attacker quickly disabled administrator access to VSA, according to Beaumont, and then inserted a task called "Kaseya VSA Agent Hot-fix." This phoney update was then pushed out to the entire estate, including MSP client systems. The management agent update was actually REvil ransomware, and non-Kaseya customers were still encrypted. The ransomware allowed hackers to disable antivirus software and run a phoney Windows Defender app, after which the computer's files were encrypted and couldn't be viewed without a key.

Windows 10 New Feature Hunts and Thwarts PUAs/PUPs


Per reports, Microsoft has hinted that the next main version of Windows 10 will come stacked with a fresh security feature that would allow the users to facilitate the Windows Defender’s secret feature that helps hunt and bar the installation of known PUAs (Potentially Unwanted Applications).

PUA’s are also widely known as PUPs that stands for Potentially Unwanted Programs. These aren’t as well known by the users in the cyber-crime world as all the other major threats but are a valid threat nevertheless.

Per sources, these are software that is installed on devices via fooling the targets. The term for which the PUP/PUA stands is self-explanatory with regards to applications or programs that your device may not really need.

PUPs/PUAs go around with tactics like either by employing “silent installs” to dodge user permissions or by “bundling” an unrequired application with the installer of an authentic program.

Sources mention that PUAs most commonly contain applications that alter browser history, hinder security controls, install root certificates, track users and sell their data, and display invasive ads.

As per reports, the May 2020 update is to be rolled out to the users in the last week of this month. Microsoft mentioned that it has added a fresh new feature in its setting panel that would allow users to bar the installation of any unwanted applications or programs in the form of known PUAs/PUPs.

As it turns out, researchers mention that the feature has been available in the Windows Defender for quite a lot of time, but for it to kick start it would need group policies and not the usual Windows user interface.

As per sources, to enable the feature a user must go to ‘Start’, ‘Settings’, ‘Update & Security’, ‘Windows Security’, ‘App & Browser Control’, and finally 'Reputation-based Protection Settings’. Once updated, the feature would show two settings, the above-mentioned feature is disabled by default and would need to be enabled manually. However, Microsoft suggests, enabling both the settings.

Reports mention, that the “Block Apps” feature will scan for PUAs that have already been downloaded or installed, so if the user’s using a different browser Windows Security would intercept it after it’s downloaded. However, the “Block Downloads” feature hunts the PUAs while they are being downloaded.

Modified TrickBot Trojan can now Steal Windows Active Directory Credentials


TrickBot trojan, a strain of malware that has been around affecting users since 2016 - is now evolved to steal Windows Active Directory credentials. Today, in the cybersecurity ecosystem it is considered as one of the top threats abusing businesses, experts estimate that TrickBot is responsible for compromising more than 250 million email accounts till date. Earlier, TrickBot went a step further while targeting Windows 10 users by disabling Windows defender onto their systems rather than just bypassing the protection. Fundamentally, TrickBot is a banking Trojan and is generally deployed through spearphishing emails like invoices mailed to the accounts department. Typically, it is attached as infected Microsoft Excel or Word documents. The malware can be spread across an organization in a number of ways, one of them is via exploiting vulnerabilities in a protocol called SMB which makes the process of sharing and accessing files on other systems easy for Windows computers.

First identified by Sandor Nemes, a security researcher from Virus Total, this new module of TrickBot dubbed as "ADII" further amplifies the threat it possesses for security, it steals Windows Active Directory information by executing a set of commands.

An Active Directory database is being created and stored into the default C:\Windows\NTDS folder on the domain controller, a server here is acting as the domain controller. Now, all the information including passwords, computers, users, and groups of Windows Active Directory are saved in a file by the name "ntds.dit" in the database. As all the aforementioned information is sensitive in nature, Windows resort to a BootKey that is located in the system component of the Registry and encrypts the information with the help of it. Admins who are responsible for database maintenance use a special tool known as "ntdsutil" to work with that database. Reportedly, standard file operations cannot access the BootKey.

How TrickBot Goes About Stealing Active Directory Credentials?


Administrators use the command "install from media", also known as "ifm", to create a dump of Active Directory. The command leads to the creation of an installation media for setting up new Domain Controllers. The new module "ADII" exploits the ifm command to produce a copy of the Windows Active Directory database; after the database is dumped into the %Temp% folder, the bot collects the information and transfers it to the admin. The collected data can be effective in infecting more systems in the same network and could also be employed by various other malware in search of similar vulnerabilities.

Legitimate Apps That Could Be Exploited To Bypass The Windows Defender: Microsoft’s List



Microsoft recently, published a conspicuous list of application that are legitimate and yet could be exploited by hackers to bypass the Windows defender.


These hackers try to slide into the organizations’ networks and infect them via bypassing the security imparted by the defender.

The hackers usually make use of off-the-land attack tactics where they use the victim’s operating system features or authentic network administration tools to compromise the networks.

The major motive of this project was to comprehend the binaries that were being misused by the attacker.

·       LOLBins- Living Off The Land Binaries
·       LOLScripts- Living Off The Land Scripts
·       LOLLibs- Living Off The Land Libraries
·       GTFOBins- Unix Platform Binaries

The only point of fusing the legitimate app is to stay undetected in order to bypass the security measures of the network.

The LOTL tools are just a way to be as stealthy as possible as be as malignant as possible without even being easily caught.

The following applications are in the list that Microsoft published and recommend to do away with if not in use:
·       addinprocess.exe
·       addinprocess32.exe
·       addinutil.exe
·       bash.exe
·       bginfo.exe[1]
·       cdb.exe
·       csi.exe
·       dbghost.exe
·       dbgsvc.exe
·       dnx.exe
·       fsi.exe
·       fsiAnyCpu.exe
·       kd.exe
·       ntkd.exe
·       lxssmanager.dll
·       msbuild.exe[2]
·       mshta.exe
·       ntsd.exe
·       rcsi.exe
·       system.management.automation.dll
·       windbg.exe
·       wmic.exe

Along with the published list Microsoft has also highly recommended the users to download latest security updates.

In addition it has also provided the “deny file rules” for all apps.

Lateral movement and defense evasion happen to be the mostly used ways to exploit the authentic applications.