Email is one of the primary modes of communication in businesses worldwide. With intense reliance on email services, companies need to ensure that their email security gateway (ESG) is robust enough to protect them from potential cyber-attacks that could compromise sensitive information. However, even with extensive security measures in place, sometimes hackers find a way to penetrate the defenses.
Recently, Barracuda, the email protection and network security services provider, disclosed a zero-day flaw that was exploited to breach the company’s Email Security Gateway (ESG) appliances. Let’s take a look at what happened.
Description of zero-day vulnerability
The vulnerability, which is being tracked as CVE-2023-2868, has been described as a remote code injection vulnerability that affects ESG versions 5.1.3.001 through 9.2.0.006. Remote code injection involves attackers injecting malicious code into an application, which then executes a command on the server without the user’s knowledge.
Cause of vulnerability
Barracuda’s investigation showed that the vulnerability arose from a failure to comprehensively sanitize the processing of .tar files (tape archives). Attackers could leverage the issue to bypass email filters by including malicious code within a .tar file sent over email.
Discovery and immediate patching by Barracuda
The vulnerability was identified on May 19, 2023, prompting Barracuda to deploy a patch across all ESG devices worldwide a day later. The company commended its timely action to protect its users’ data from potential exploitation through the vulnerability.
As part of its containment strategy, the company released another fix on May 21st, attempting to address other potential weaknesses in its ESG appliances. The patch was designed to prevent the exploitation of future vulnerabilities.
Evidence of active exploitation
Barracuda uncovered evidence of active exploitation of CVE-2023-2868, resulting in unauthorized access to a “subset of email gateway appliances.” However, the company did not disclose the scale of the attack or the geographical distribution of the affected ESG devices.
Direct communication with affected users
Barracuda has been proactive in informing its customers who may have been affected by the CVE-2023-2868 vulnerability. They have said that affected users have been directly contacted with a list of remedial actions to take, ensuring that they are aware of the issue and how to respond.
Urging customers to review their environments
In addition to notifying its customers who had been affected, Barracuda has advised all customers to review their ESG environments, adding that it’s still actively monitoring the situation. The company has also stated that it won’t share any details that could exacerbate the situation for affected customers.
Possible threat actors
At present, the identity of the threat actors behind the attack is still under investigation. However, in recent months, Chinese and Russian hacking groups have deployed bespoke malware on vulnerable devices such as Cisco, Fortinet, and SonicWall. The attackers undertook this action to steal data, compromise systems, or deploy ransomware. It’s possible that the perpetrators of this Barracuda ESG breach may be affiliated with one of these groups, or an as-yet-unknown set of hackers.
Barracuda email gateway appliances provide a vital layer of protection that businesses rely on to keep their communications secure. The recent ESG breach highlights the critical need for businesses to remain vigilant and stay proactive in securing their infrastructure to prevent cyberattacks. As cybercriminals continue to evolve their tactics, businesses must do the same to keep their defenses up-to-date and catch new vulnerabilities as they appear. The key takeaway from this Barracuda incident is that no company is entirely immune from a security breach, and preparing for the worst is essential to minimize the potential impact of an attack.