A brand new variant of the Mirai malware botnet is exploiting a command injection vulnerability in TBK DVR-4104 and DVR-4216 digital video recording units to hijack them.
The flaw, tracked underneath CVE-2024-3721, is a command injection vulnerability disclosed by security researcher “netsecfish” in April 2024.
The proof-of-concept (PoC) the researcher printed on the time got here within the type of a specifically crafted POST request to a weak endpoint, reaching shell command execution by means of the manipulation of sure parameters (mdb and mdc).
Kaspersky now experiences having caught lively exploitation of CVE-2024-3721 in its Linux honeypots from a brand new Mirai botnet variant utilizing netsecfish’s PoC.
The attackers leverage the exploit to drop an ARM32 malware binary, which establishes communication with the command and management (C2) server to enlist the system to the botnet swarm. From there, the system is probably going used to conduct distributed denial of service (DDoS) assaults, proxy malicious visitors, and different conduct.

Supply: Kaspersky
Attack affect and fixes
Though netsecfish reported final yr that there have been roughly 114,000 internet-exposed DVRs weak to CVE-2024-3721, Kaspersky’s scans present roughly 50,000 uncovered units, which continues to be vital.
Most infections the Russian cybersecurity agency sees as being related to the most recent Mirai variant affect China, India, Egypt, Ukraine, Russia, Turkey, and Brazil. Nevertheless, that is primarily based on Kaspersky’s telemetry, and as its client security merchandise are banned in lots of international locations, this may occasionally not precisely replicate the botnet’s focusing on focus.
At the moment, it’s unclear if the seller, TBK Imaginative and prescient, has launched security updates to handle the CVE-2024-3721 flaw or if it stays unpatched. BleepingComputer contacted TBK to ask about this, however we’re nonetheless ready for his or her response.
It is price noting that DVR-4104 and DVR-4216 have been extensively re-branded underneath the Novo, CeNova, QSee, Pulnix, XVR 5 in 1, Securus, Evening OWL, DVR Login, HVR Login, and MDVR manufacturers, so the supply of patches for impacted units is a posh matter.
The researcher who disclosed the TBK Imaginative and prescient flaw found different flaws that fueled exploitation in opposition to end-of-life units final yr.
Particularly, netsecfish has disclosed a backdoor account problem and a command injection vulnerability impacting tens of 1000’s of EoL D-Hyperlink units in 2024.
Lively exploitation was detected in each circumstances only some days after the PoC’s disclosure. This exhibits how rapidly malware authors incorporate public exploits into their arsenal.
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