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Organizations Quick to Patch Critical Citrix ADC Vulnerability

More than 80 percent of organizations impacted by CVE-2019-19781, a critical vulnerability in the Citrix Application Delivery Controller (ADC) and Gateway, have already taken steps to secure their deployments. 

More than 80 percent of organizations impacted by CVE-2019-19781, a critical vulnerability in the Citrix Application Delivery Controller (ADC) and Gateway, have already taken steps to secure their deployments. 

Disclosed in December 2019 and exploited in the wild shortly after, the vulnerability was estimated to expose around 80,000 companies in 158 countries to remote attacks. 

The security bug impacts multiple versions of Citrix ADC and Gateway (previously known as NetScaler ADC and NetScaler Gateway), but Citrix has already released permanent patches for all of them, as attacks started to ramp up. The company also published a tool to detect compromise.

Now, more than one month and a half after publishing their initial assessment of the vulnerability, Positive Technologies, the security firm that discovered the bug, says that one in five vulnerable companies has yet to action to fix their Citrix ADC installations. 

The vulnerability is being patched quickly, but 19 percent of companies are still exposed, the enterprise security solutions firm says. This means that more than 15,000 companies continue to be vulnerable.

At the moment, Brazil has the largest number of affected companies, as 43% of those where the vulnerability was originally detected have yet to apply a fix. China comes in second at 39%, followed by Russia at 35%, France at 34%, Italy and 33%, and Spain at 25%. 

The United States, the United Kingdom, and Australia, which were some of the most affected countries when the flaw was discovered (in December 2019, over 38% of all vulnerable organizations were located in the U.S.), each have 21 percent of companies still using vulnerable deployments. 

Successful exploitation of the vulnerability results in attackers gaining direct access to the organization’s local network. No account credentials are required to mount an assault from the Internet. 

In addition to permanent patches for the vulnerability, Citrix published mitigation steps that organizations can take to secure their Citrix ADC and Gateway deployments. Affected organizations are strongly advised to apply either of those to remain protected. 

“The Citrix developers planned to resolve the issue on January 27 through January 31, but released a series of patches for various product versions a week before that. The necessary update must be installed as soon as possible. Until then, follow the security recommendations by Citrix, available since the information about the vulnerability was released,” says Alexei Novikov, Director of PT Expert Security Center.

Related: Attacks on ADC Ramp Up as Citrix Releases Remaining Patches

Related: Citrix Releases More Patches for Exploited Flaw, Tool to Detect Compromise

Related: Citrix Releases First Patches for Critical ADC Vulnerability

Written By

Ionut Arghire is an international correspondent for SecurityWeek.

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