Microsoft Exchange | Breaking Cybersecurity News | The Hacker News

Threat actors are actively carrying out opportunistic  scanning  and  exploitation  of Exchange servers using a new exploit chain leveraging a trio of flaws affecting on-premises installations, making them the latest set of bugs after ProxyLogon vulnerabilities were exploited en masse at the start of the year. The remote code execution flaws have been collectively dubbed "ProxyShell." At least 30,000 machines are affected by the vulnerabilities,  according  to a Shodan scan performed by Jan Kopriva of SANS Internet Storm Center. "Started to see in the wild exploit attempts against our honeypot infrastructure for the Exchange ProxyShell vulnerabilities," NCC Group's Richard Warren  tweeted , noting that one of the intrusions resulted in the deployment of a "C# aspx webshell in the /aspnet_client/ directory." Patched in early March 2021,  ProxyLogon  is the moniker for CVE-2021-26855, a server-side request forgery vulnerability in Exchange Server tha

The U.S. government and its key allies, including the European Union, the U.K., and NATO, formally attributed the massive cyberattack against Microsoft Exchange email servers to state-sponsored hacking crews working affiliated with the People's Republic of China's Ministry of State Security (MSS). In a  statement  issued by the White House on Monday, the administration said, "with a high degree of confidence that malicious cyber actors affiliated with PRC's MSS conducted cyber-espionage operations utilizing the zero-day vulnerabilities in Microsoft Exchange Server disclosed in early March 2021. The U.K. government  accused  Beijing of a "pervasive pattern of hacking" and "systemic cyber sabotage." The  sweeping espionage campaign  exploited four previously undiscovered vulnerabilities in Microsoft Exchange software and is believed to have hit at least 30,000 organizations in the U.S. and hundreds of thousands more worldwide. Microsoft identified

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Attackers are exploiting the ProxyLogon Microsoft Exchange Server flaws to co-opt vulnerable machines to a cryptocurrency botnet named Prometei, according to new research. "Prometei exploits the recently disclosed Microsoft Exchange vulnerabilities associated with the HAFNIUM attacks to penetrate the network for malware deployment, credential harvesting and more," Boston-based cybersecurity firm Cybereason  said  in an analysis summarizing its findings. First documented by Cisco Talos in July 2020,  Prometei  is a multi-modular botnet, with the actor behind the operation employing a wide range of specially-crafted tools and known exploits such as EternalBlue and BlueKeep to harvest credentials, laterally propagate across the network and "increase the amount of systems participating in its Monero-mining pool." "Prometei has both Windows-based and Linux-Unix based versions, and it adjusts its payload based on the detected operating system, on the targeted in

In its April slate of patches, Microsoft rolled out fixes for a total of  114 security flaws , including an actively exploited zero-day and four remote code execution bugs in Exchange Server. Of the  114 flaws , 19 are rated as Critical, 88 are rated Important, and one is rated Moderate in severity. Chief among them is  CVE-2021-28310 , a privilege escalation vulnerability in Win32k that's said to be under active exploitation, allowing attackers to elevate privileges by running malicious code on a target system.  Cybersecurity firm Kaspersky, which discovered and reported the flaw to Microsoft in February, linked the zero-day exploit to a threat actor named Bitter APT, which was found exploiting a similar flaw ( CVE-2021-1732 ) in attacks late last year. "It is an escalation of privilege (EoP) exploit that is likely used together with other browser exploits to escape sandboxes or get system privileges for further access," Kaspersky researcher Boris Larin  said . NS

Microsoft on Monday released a one-click mitigation software that applies all the necessary countermeasures to secure vulnerable environments against the ongoing widespread  ProxyLogon Exchange Server  cyberattacks. Called Exchange On-premises Mitigation Tool ( EOMT ), the PowerShell-based script serves to mitigate against current known attacks using CVE-2021-26855, scan the Exchange Server using the  Microsoft Safety Scanner  for any deployed web shells, and attempt to remediate the detected compromises. "This new tool is designed as an interim mitigation for customers who are unfamiliar with the patch/update process or who have not yet applied the on-premises Exchange security update," Microsoft  said . The development comes in the wake of indiscriminate attacks against unpatched Exchange Servers across the world by more than ten advanced persistent threat actors — most of the government-backed cyberespionage groups — to plant backdoors, coin miners, and  ransomware ,

It didn't take long. Intelligence agencies and cybersecurity researchers had been warning that unpatched Exchange Servers could open the pathway for ransomware infections in the wake of swift escalation of the attacks since last week. Now it appears that threat actors have caught up.  According to the latest reports , cybercriminals are leveraging the heavily exploited ProxyLogon Exchange Server flaws to install a new strain of ransomware called "DearCry." "Microsoft observed a new family of human operated ransomware attack customers – detected as Ransom:Win32/DoejoCrypt.A," Microsoft researcher Phillip Misner  tweeted . "Human operated ransomware attacks are utilizing the Microsoft Exchange vulnerabilities to exploit customers." Microsoft's security intelligence team, in a separate tweet,  confirmed  that it has begun "blocking a new family of ransomware being used after an initial compromise of unpatched on-premises Exchange Servers.&q

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) and the Federal Bureau of Investigation (FBI) on Wednesday issued a joint advisory warning of active exploitation of vulnerabilities in Microsoft Exchange on-premises products by nation-state actors and cybercriminals. "CISA and FBI assess that adversaries could exploit these vulnerabilities to compromise networks, steal information, encrypt data for ransom, or even execute a destructive attack," the agencies  said . "Adversaries may also sell access to compromised networks on the dark web." The attacks have primarily targeted local governments, academic institutions, non-governmental organizations, and business entities in various industry sectors, including agriculture, biotechnology, aerospace, defense, legal services, power utilities, and pharmaceutical, which the agencies say are in line with previous activity conducted by Chinese cyber actors. Tens of thousands of entities, including the  Eur

The European Banking Authority (EBA) on Sunday said it had been a victim of a cyberattack targeting its Microsoft Exchange Servers, forcing it to temporarily take its email systems offline as a precautionary measure. "As the vulnerability is related to the EBA's email servers, access to personal data through emails held on that servers may have been obtained by the attacker," the Paris-based regulatory agency  said . EBA said it's launched a full investigation into the incident in partnership with its information and communication technology (ICT) provider, a team of forensic experts, and other relevant entities. In a second update issued on Monday, the agency said it had secured its email infrastructure and that it found no evidence of data extraction, adding it has "no indication to think that the breach has gone beyond our email servers." Besides deploying extra security measures, EBA also noted it's closely monitoring the situation after restor

Microsoft on Friday warned of active attacks exploiting unpatched Exchange Servers carried out by multiple threat actors, as the hacking campaign is believed to have infected tens of thousands of businesses, government entities in the U.S., Asia, and Europe. The company  said  "it continues to see increased use of these vulnerabilities in attacks targeting unpatched systems by multiple malicious actors beyond HAFNIUM," signaling an escalation that the breaches are no longer "limited and targeted" as was previously deemed. According to independent cybersecurity journalist  Brian Krebs , at least 30,000 entities across the U.S. — mainly small businesses, towns, cities, and local governments — have been compromised by an "unusually aggressive" Chinese group that has set its sights on stealing emails from victim organizations by exploiting previously undisclosed flaws in Exchange Server. Victims are also being reported from outside the U.S., with email s