When threat actors use backdoor malware to gain access to a network, they want to make sure all their hard work can’t be leveraged by competing groups or detected by defenders. One countermeasure is to equip the backdoor with a passive agent that remains dormant until it receives what’s known in the business as a “magic packet.” On Thursday, researchers revealed that a never-before-seen backdoor that quietly took hold of dozens of enterprise VPNs running Juniper Network’s Junos OS has been doing just that.
**Meet J-Magic, the Stealthy Backdoor**
The tracking name for this backdoor is J-Magic, and it’s a clever piece of malware that’s been evading detection for quite some time. After receiving a magic packet hidden in the normal flow of TCP traffic, it relays a challenge to the device that sent it. The challenge comes in the form of a string of text that’s encrypted using the public portion of an RSA key. The initiating party must then respond with the corresponding plaintext, proving it has access to the secret key.
**A Masterclass in Stealth**
What makes J-Magic particularly noteworthy is that it resides only in memory, a trait that makes detection harder for defenders. This lightweight backdoor is designed to remain undetected, and its ability to send and receive magic packets without leaving any trace is a testament to its creators’ expertise.
**A Wake-Up Call for Defenders**
The discovery of J-Magic is a wake-up call for defenders, highlighting the need for more sophisticated detection methods and incident response plans. As cyber threats continue to evolve, it’s essential for organizations to stay one step ahead of attackers and invest in robust security measures that can detect and respond to threats in real-time.
**Source:**
* Lumen Technology’s Black Lotus Lab
* Juniper Networks
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