The education sector in the US has recently been targeted by the Bl00dy Ransomware Gang, who have been exploiting vulnerable PaperCut servers. According to a joint advisory by the Federal Bureau of Investigation (FBI) and Cybersecurity and Infrastructure Security Agency (CISA), the attacks occurred in early May 2021.
The Bloody Ransomware Gang has gained access to victim networks across the Education Facilities Subsector, where PaperCut servers that were vulnerable to CVE-2023-27350 were exposed to the internet. This has given the attackers the opportunity to exfiltrate data and encrypt victim systems.
The exploitation of CVE-2023-27350, a critical security flaw that enables remote code execution, has been observed since mid-April 2023. The vulnerability affects some versions of PaperCut MF and NG, which attackers have used as a means of entry to victim networks.
The attackers left ransom notes on the compromised systems, demanding payment in exchange for decrypting encrypted files. The incidents have caused significant disruptions to the education sector, which has proven to be a prime target for cyberattacks.
CVE-2023-27350: A critical security flaw
CVE-2023-27350 is a now-patched critical security flaw affecting some versions of PaperCut MF and NG. It enables remote actors to bypass authentication and conduct remote code execution, providing a gateway for attackers to compromise victim networks.
The exploitation of the vulnerability has been ongoing since mid-April 2021, with malicious actors deploying it to drop additional payloads such as Cobalt Strike Beacons, DiceLoader, and TrueBot on compromised systems. The attackers primarily weaponized the vulnerability to deploy legitimate remote management and maintenance (RMM) software.
Exploitation of CVE-2023-27350 to Drop Cryptocurrency Miner
eSentire, a cybersecurity firm, recently uncovered new activities targeting an unnamed education sector customer. The activity involved the exploitation of CVE-2023–27350 to drop an XMRig cryptocurrency miner. This is indicative of the increasing trend of attackers deploying cryptocurrency miners as a means of monetizing their attacks.
PaperCut Print Management Servers have been targeted by Iranian state-sponsored threat groups
As if the education sector wasn’t facing enough trouble, Microsoft recently revealed that Iranian state-sponsored threat groups, Mango Sandstorm (aka MuddyWater or Mercury), and Mint Sandstorm (aka Phosphorus), have been targeting PaperCut print management servers.
These threat groups have been deploying sophisticated hacking tools with complex capabilities including droppers, loaders, and command-and-control (C2) servers to exfiltrate sensitive data. The attacks have highlighted the need for organizations to bolster their cybersecurity defenses against a range of cyber threats.
The Bloody Ransomware Gang’s attacks against the education sector in the US demonstrate the growing threat that the sector faces from cyberattacks. The exploitation of the CVE-2023-27350 vulnerability highlights the importance of promptly patching vulnerabilities in software and systems to protect against potential exploits.
With cybercriminals and state-sponsored threat groups deploying increasingly advanced attack methods, organizations across all sectors must step up their cybersecurity game to safeguard their networks and data against attacks. It is essential to develop robust cybersecurity strategies that can detect and respond to attacks before they cause significant damage.