What is SysJoker malware what are the dangerous?

A new sort of malware was detected sneaking into a Linux-based server in the final days of 2021. Worryingly, it has been discovered to be undetected by antivirus software and to have numerous forms, allowing it to infect Windows, macOS, and Linux computers. This new piece of malware, dubbed SysJoker, should be on everyone's radar.

It may run on a variety of well-known operating systems, including Windows, macOS, and Linux. For several months, he managed to avoid the radars of the cyber universe's numerous systems, software, and detection platforms. Finally, experts at Intezer, a New York-based computer security firm, discovered this new type of malware that serves as a back door (backdoor).

SysJoker's Threats

  • In general, SysJoker is available in a variety of flavors for Linux, Windows, and macOS.

  • It can then use that information to construct a sequence of files and registry commands that allow it to install other malware, run commands on the infected device, and shut down the backdoor.

  • This malware is a severe hazard since it may make itself undetected by antivirus software.

  • For the time being, the only way to tell if suspected victims have the virus is to manually examine their computers for generated files.

What distinguishes SysJoker from other backdoors?

In late December 2021, SysJoker was identified in the middle of an assault on the web servers of a "major educational institution." While it was previously thought that the bug only affected Linux computers, it was soon determined that it also affected Windows and Mac OS X. The initial assault, according to Intezer, the security firm that discovered it, may have occurred earlier this year.

Only the victim has the ability to activate SysJoker. The program, which is disguised as a system update, must be downloaded and installed by the user. This basic kind of deception heightens the threat posed by socially engineered cyber assaults.SysJoker differs from previous malware in that it appears to have been created from the ground up rather than being based on existing malware. In fact, the malware's intricacy, along with the fact that it's connected to four separate command-and-control servers, suggests that a great amount of time and effort went into developing it. It isn't from your average cybercriminal. SysJoker was built by someone who understands what they're doing.

It can continue to receive additions and instructions from the many command-and-control servers. With urging from the control servers, SysJoker has the ability to grow more powerful or gain greater capabilities over time.


Under Windows, SysJoker includes a first-level injector in the form of a DLL, that will be introduced into the system, allowing PowerShell commands to decompress and run SysJoker (which is then in ZIP format). After 90 to 120 seconds of inactivity, SysJoker creates a new directory (C: ProgramDataSystemData) and installs the Intel Graphics Common User Interface Service (igfxCUIService.exe), which is nothing more than a software component that installs alongside the drivers for Intel graphics cards and is an integral part of the brand's user interface.

What's the next stage in the process? Between each level, SysJoker spends time acquiring information about the machine, resting for an unknown period of time. After some time, he decodes a Google Drive link that is practically hard-coded and accesses a file that provides the address of the command and control servers (C2 or C&C), a file that can also vary over time. Finally, SysJoker is able to gather the information required to run commands (exe, cmd, remove reg, and quit) or install malware.

How do you find SysJoker and get rid of it?

SysJoker is nearly invisible by most virus-scanning tools due to its recent detection. Fortunately, there are methods for determining whether your machine has been infected with this especially tenacious problem.

On their computers, users can run a memory scanner. A memory scanner can identify the SysJoker data payload, which your conventional antivirus package won't be able to detect. When SysJoker is found, you must remove any new SysJoker files and terminate all SysJoker- related processes.

Run a memory scan one more after this step to ensure that all traces of SysJoker have been eliminated. Now that your systems have been cleaned, it's time to identify the malware's entrance point. Keep in mind that SysJoker requires the user to download and install the program on their own.

How to avoid getting SysJoker on your machine

The easiest approach to keep SysJoker from wreaking havoc on your network is to brush up on fundamental cybersecurity best practices. If you receive an email or message with a questionable link, don't even think about trying to figure out who sent it. It should be thrown out immediately. Hackers take advantage of consumers' gullibility.

SysJoker pretends to be a system update. SysJoker has no method of contacting you if you haven't downloaded anything from any suspicious websites or clicked on any strange links. Furthermore, SysJoker was attacking an educational system and appeared to have been developed with a large budget.

Updated on: 16-Mar-2022


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