“Highly capable” hackers root corporate networks by exploiting firewall 0-day

Highly capable hackers are rooting multiple corporate networks by exploiting a maximum-severity zero-day vulnerability in a firewall product from Palo Alto Networks, researchers said Friday.

The vulnerability, which has been under active exploitation for at least two weeks now, allows the hackers with no authentication to execute malicious code with root privileges, the highest possible level of system access, researchers said. The extent of the compromise, along with the ease of exploitation, has earned the CVE-2024-3400 vulnerability the maximum severity rating of 10.0. The ongoing attacks are the latest in a rash of attacks aimed at firewalls, VPNs, and file-transfer appliances, which are popular targets because of their wealth of vulnerabilities and direct pipeline into the most sensitive parts of a network.

“Highly capable” UTA0218 likely to be joined by others

The zero-day is present in PAN-OS 10.2, PAN-OS 11.0, and/or PAN-OS 11.1 firewalls when they are configured to use both the GlobalProtect gateway and device telemetry. Palo Alto Networks has yet to patch the vulnerability but is urging affected customers to follow the workaround and mitigation guidance provided here. The advice includes enabling Threat ID 95187 for those with subscriptions to the company’s Threat Prevention service and ensuring vulnerability protection has been applied to their GlobalProtect interface. When that’s not possible, customers should temporarily disable telemetry until a patch is available.

Volexity, the security firm that discovered the zero-day attacks, said that it’s currently unable to tie the attackers to any previously known groups. However, based on the resources required and the organizations targeted, they are “highly capable” and likely backed by a nation-state. So far, only a single threat group—which Volexity tracks as UTA0218—is known to be leveraging the vulnerability in limited attacks. The company warned that as new groups learn of the vulnerability, CVE-2024-3400, is likely to come under mass exploitation, just as recent zero-days affecting products from the likes of Ivanti, Atlassian, Citrix, and Progress have in recent months.

“As with previous public disclosures of vulnerabilities in these kinds of devices, Volexity assesses that it is likely a spike in exploitation will be observed over the next few days by UTA0218 and potentially other threat actors who may develop exploits for this vulnerability,” company researchers wrote Friday. “This spike in activity will be driven by the urgency of this window of access closing due to mitigations and patches being deployed. It is therefore imperative that organizations act quickly to deploy recommended mitigations and perform compromise reviews of their devices to check whether further internal investigation of their networks is required.”

The earliest attacks Volexity has seen took place on March 26 in what company researchers suspect was UTA0218 testing the vulnerability by placing zero-byte files on firewall devices to validate exploitability. On April 7, the researchers observed the group trying unsuccessfully to install a backdoor on a customer’s firewall. Three days later, the group’s attacks were successfully deploying malicious payloads. Since then, the threat group has deployed custom, never-before-seen post-exploitation malware. The backdoor, which is written in the Python language, allows the attackers to use specially crafted network requests to execute additional commands on hacked devices.