Governance & Risk Management , Network Firewalls, Network Access Control , Patch Management

The Peril of Badly Secured Network Edge Devices

Poorly Protected Firewalls, VPNs and Remote Access Protocol Increase Breach Risk
The Peril of Badly Secured Network Edge Devices
Cracks in cyber defenses occur when organizations don't carefully tend to network edge devices. (Image: Shutterstock)

Boundary devices offering firewall and remote access capabilities are ubiquitous. But unless such appliances are rapidly patched, well-monitored with logs and otherwise carefully locked down, they pose a clear and present enterprise cybersecurity liability.

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The specific risk posed by poorly managed devices is quantified in a new report from cyber insurer Coalition.

While firewalls and virtual private networks can reduce risk, analysis of 2023 claims data shows that "boundary devices with known vulnerabilities increased the likelihood of a business experiencing a cyber claim," including ransomware.

The biggest risks involved anyone using internet-exposed Cisco Adaptive Security Appliance devices, who were five times more likely than non-ASA users to file a claim. Users of internet-exposed Fortinet devices were twice as likely to file a claim.

Another risk comes in the form of Remote Desktop Protocol. Organizations with internet-exposed RDP filed 2.5 times as many claims as organizations without it, Coalition said. Mass scanning by attackers, including initial access brokers, to detect and exploit poorly protected RDP connections remains rampant. Coalition said that last year from January to October, its honeypots detected a 59% increase in the quantity of unique IP addresses being used to scan for RDP connections.

The sheer quantity of new vulnerabilities coming to light underscores the ongoing risks network edge devices pose. For example, new and exploitable flaws in Fortinet devices continued to be discovered throughout 2023 and into the beginning of this year.

Likewise for Cisco hardware: "Several critical vulnerabilities impacting Cisco ASA devices were discovered in 2023, likely contributing to the increased relative frequency," Coalition said.

In many cases, organizations fail to patch these vulnerabilities, leaving them at increased risk, including by attackers targeting the Cisco AnyConnect vulnerability, designated as CVE-2020-3259, which the vendor first disclosed in May 2020.

Cybersecurity firm Truesec's computer security incident response team warned in January that the Akira ransomware group continues to exploit CVE-2020-3259 to gain initial access on numerous devices and then remotely access enterprise networks.

Based on its policyholder data, Coalition said exploits of that vulnerability by Akira have been posing "a significant risk for businesses that has continued into 2024."

Organizations that fail to patch known flaws in devices aren't the only ones at risk from adversaries seeking to exploit commodity boundary devices as an entry vector for their attacks.

This week, networking giant Cisco warned that a sophisticated nation-state campaign targeted at least a small number of government users of its ASA appliances, sneaking backdoors onto the devices (see: Cisco Fixes Firewall 0-Days After Likely Nation-State Hack).

Cisco said it first received an alert early this year suggesting that attackers were exploiting ASA software or its Firepower Threat Defense "to implant malware, execute commands and potentially exfiltrate data from the compromised devices."

The manufacturer said the full details of the attack campaign, which has the codename ArcaneDoor and which seems to have ramped up last November, have yet to come to light, including how attackers initially targeted devices later confirmed to be hacked. Even so, Cisco released updates to patch two vulnerabilities - CVE-2024-20353 and CVE-2024-20359 - exploited by the attackers and urged users of all devices that run either ASA or FTD software to update it immediately, saying there is no other way to mitigate the attacks.

As a further impetus to rapidly patch the flaws, the company warned that boundary networking devices remain a top target for attackers - and not least for nation-state groups running cyber operations and espionage campaigns.

"Perimeter network devices are the perfect intrusion point for espionage-focused campaigns," said Cisco's Talos threat intelligence group. "As a critical path for data into and out of the network, these devices need to be routinely and promptly patched; using up-to-date hardware and software versions and configurations; and be closely monitored from a security perspective."

If hacked, such devices can be subverted by hackers to spy on communications, reroute traffic, gain access to other parts of the network and more, experts warn.

"In the past two years, we have seen a dramatic and sustained increase in the targeting of these devices in areas such as telecommunications providers and energy sector organizations - critical infrastructure entities that are likely strategic targets of interest for many foreign governments," Cisco Talos said.

About the Author

Mathew J. Schwartz

Mathew J. Schwartz

Executive Editor, DataBreachToday & Europe, ISMG

Schwartz is an award-winning journalist with two decades of experience in magazines, newspapers and electronic media. He has covered the information security and privacy sector throughout his career. Before joining Information Security Media Group in 2014, where he now serves as the executive editor, DataBreachToday and for European news coverage, Schwartz was the information security beat reporter for InformationWeek and a frequent contributor to DarkReading, among other publications. He lives in Scotland.

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