Exchange Server | Breaking Cybersecurity News | The Hacker News

Cybersecurity researchers have shed light on a previously undocumented threat actor called NightEagle (aka APT-Q-95) that has been observed targeting Microsoft Exchange servers as a part of a zero-day exploit chain designed to target government, defense, and technology sectors in China. According to QiAnXin's RedDrip Team, the threat actor has been active since 2023 and has switched network infrastructure at an extremely fast rate. The findings were presented at CYDES 2025 , the third edition of Malaysia's National Cyber Defence & Security Exhibition and Conference held between July 1 and 3, 2025. "It seems to have the speed of an eagle and has been operating at night in China," the cybersecurity vendor said , explaining the rationale behind naming the adversary NightEagle. Attacks mounted by the threat actor have singled out entities operating in the high-tech, chip semiconductors, quantum technology, artificial intelligence, and military verticals with th...

Microsoft on Wednesday acknowledged that a newly disclosed critical security flaw in Exchange Server has been actively exploited in the wild, a day after it released fixes for the vulnerability as part of its  Patch Tuesday updates . Tracked as  CVE-2024-21410  (CVSS score: 9.8), the issue has been described as a case of privilege escalation impacting the Exchange Server. "An attacker could target an NTLM client such as Outlook with an NTLM credentials-leaking type vulnerability," the company  said  in an advisory published this week. "The leaked credentials can then be relayed against the Exchange server to gain privileges as the victim client and to perform operations on the Exchange server on the victim's behalf." Successful exploitation of the flaw could permit an attacker to relay a user's leaked Net-NTLMv2 hash against a susceptible Exchange Server and authenticate as the user, Redmond added. The tech giant, in an update to its bulletin, revised...

In the current digital landscape, data has emerged as a crucial asset for organizations, akin to currency. It's the lifeblood of any organization in today's interconnected and digital world. Thus, safeguarding the data is of paramount importance. Its importance is magnified in on-premises Exchange Server environments where vital business communication and emails are stored and managed.  In this article, you will learn about the evolving threats of data loss, the shift in responsibilities of administrators, and key backup and recovery strategies for preventing data loss in the Exchange Server environment. Data Loss Scenarios in Exchange Servers Data loss in on-premises Exchange Server environment has become increasingly common. Cybersecurity threats, like ransomware attacks, have emerged as a significant cause of data loss in recent years, with many financially motivated threat actors increasingly targeting the vulnerabilities in Exchange Servers. These attackers try to exploit ...

Microsoft on Thursday warned of a consumer-facing attack that made use of rogue OAuth applications deployed on compromised cloud tenants to ultimately seize control of Exchange servers and spread spam. "The threat actor launched credential stuffing attacks against high-risk accounts that didn't have multi-factor authentication (MFA) enabled and leveraged the unsecured administrator accounts to gain initial access," the Microsoft 365 Defender Research Team said. The unauthorized access to the cloud tenant permitted the adversary to register a malicious OAuth application and grant it elevated permissions, and eventually modify Exchange Server settings to allow inbound emails from specific IP addresses to be routed through the compromised email server. "These modifications to the Exchange server settings allowed the threat actor to perform their primary goal in the attack: sending out spam emails," Microsoft  said . "The spam emails were sent as part of a...

Following Microsoft's release of out-of-band patches to address multiple zero-day flaws in on-premises versions of Microsoft Exchange Server, the U.S. Cybersecurity and Infrastructure Security Agency (CISA) has  issued  an emergency directive warning of " active exploitation " of the vulnerabilities. The alert comes on the heels of Microsoft's  disclosure  that China-based hackers were exploiting unknown software bugs in Exchange server to steal sensitive data from select targets, marking the second time in four months that the U.S. has scrambled to address a widespread hacking campaign believed to be the work of foreign threat actors. While the company mainly attributed the campaign to a threat group called HAFNIUM, Slovakian cybersecurity firm ESET  said  it found evidence of CVE-2021-26855 being actively exploited in the wild by several cyber espionage groups, including LuckyMouse, Tick, and Calypso targeting servers located in the U.S., Europe, Asi...