Security News

Unpatched Citrix NetScaler systems exposed to the internet are being targeted by unknown threat actors in what's suspected to be a ransomware attack. Attack chains involve the exploitation of CVE-2023-3519, a critical code injection vulnerability impacting NetScaler ADC and Gateway servers that could facilitate unauthenticated remote code execution.

A threat actor believed to be tied to the FIN8 hacking group exploits the CVE-2023-3519 remote code execution flaw to compromise unpatched Citrix NetScaler systems in domain-wide attacks. Resemblances to another attack that Sophos analysts observed earlier in the summer have led the analysts to deduce that the two activities are linked, with the threat actor specializing in ransomware attacks.

About 2,000 Citrix NetScalers were compromised in automated massive attack campaigns. Threat actors have been exploiting a NetScaler appliance vulnerability to get persistent access to the compromised systems.

Miscreants are actively exploiting critical bugs in two of Citrix's products, both of which the business IT player fixed earlier this summer. Uncle Sam's Cybersecurity and Infrastructure Security Agency on Wednesday warned that criminals have exploited CVE-2023-24489, a 9.8-of-10-severity improper-access-control bug in Citrix ShareFile.

CVE-2023-24489, a critical Citrix ShareFile vulnerability that the company has fixed in June 2023, is being exploited by attackers.GreyNoise has flagged on Tuesday a sudden spike in IP addresses from which exploitation attempts are coming, and the Cybersecurity and Infrastructure Agency has added the vulnerability to its Known Exploited Vulnerabilities Catalog.

The U.S. Cybersecurity and Infrastructure Security Agency has added a critical security flaw in Citrix ShareFile storage zones controller to its Known Exploited Vulnerabilities catalog, based on evidence of active in-the-wild exploitation. "This vulnerability affects all currently supported versions of customer-managed ShareFile storage zones controller before version 5.11.24," Citrix said in an advisory released in June.

CISA is warning that a critical Citrix ShareFile secure file transfer vulnerability tracked as CVE-2023-24489 is being targeted by unknown actors and has added the flaw to its catalog of known security flaws exploited in the wild. "A vulnerability has been discovered in the customer-managed ShareFile storage zones controller which, if exploited, could allow an unauthenticated attacker to remotely compromise the customer-managed ShareFile storage zones controller," Citrix explains.

Nearly 2,000 Citrix NetScaler instances have been compromised with a backdoor by weaponizing a recently disclosed critical security vulnerability as part of a large-scale attack. CVE-2023-3519 refers to a critical code injection vulnerability impacting NetScaler ADC and Gateway servers that could lead to unauthenticated remote code execution.

A threat actor has compromised close to 2,000 thousand Citrix NetScaler servers in a massive campaign exploiting the critical-severity remote code execution tracked as CVE-2023-3519. Security researchers at cybersecurity company Fox-IT and the Dutch Institute of Vulnerability Disclosure have discovered a large-scale campaign that planted webshells on Citrix Netscaler servers vulnerable to CVE-2023-3519.

Mandiant has released a scanner to check if a Citrix NetScaler Application Delivery Controller or NetScaler Gateway Appliance was compromised in widespread attacks exploiting the CVE-2023-3519 vulnerability. The critical CVE-2023-3519 Citrix flaw was discovered in mid-July 2023 as a zero-day, with hackers actively exploiting it to execute code remotely without authentication on vulnerable devices.