Misconfigurations in Microsoft Exchange open new doors to email spoofing attacks


A new report from the Acronis Threat Research Unit has uncovered a vulnerability in Microsoft Exchange Online settings that could enable email spoofing attacks.

This issue primarily affects users with a hybrid configuration of on-premises Exchange and Exchange Online, and those utilizing third-party email security solutions. In July 2023, Microsoft introduced a major change in how it handles DMARC (Domain-based Message Authentication, Reporting, and Conformance) within Microsoft Exchange. This update was intended to bolster security by enhancing how email servers verify incoming emails’ legitimacy. Unfortunately, despite clear guidance from Microsoft, a considerable number of users have yet to implement these security measures.

Read more…
Source: TechRadar News


Sign up for our Newsletter


Related:

  • Ivanti patched two critical zero-day vulnerabilities in EPMM

    January 30, 2026

    Ivanti has patched two critical zero-day vulnerabilities in its Endpoint Manager Mobile (EPMM) product that are already being exploited, continuing a grim run of January security incidents for enterprise IT vendors. In January 2025, tens of thousands were urged to patch a Fortinet zero-day, while Ivanti customers were doing the same. There has been little change ...

  • Microsoft Office zero-day lets malicious documents slip past security checks

    January 29, 2026

    Microsoft issued an emergency patch for a high-severity zero-day vulnerability in Office that allows attackers to bypass document security checks and is being exploited in the wild via malicious files. Microsoft pushed the emergency patch for the zero‑day, tracked as CVE-2026-21509, and classified it as a “Microsoft Office Security Feature Bypass Vulnerability” with a CVSS score ...

  • CISA: Fortinet Releases Guidance to Address Ongoing Exploitation of Authentication Bypass Vulnerability CVE-2026-24858

    January 28, 2026

    Newly disclosed vulnerability Common Vulnerabilities and Exposures (CVE)-2026-24858 allows malicious actors with a FortiCloud account and a registered device to log in to separate devices registered to other users in FortiOS, FortiManager, FortiWeb, FortiProxy, and FortiAnalyzer, if FortiCloud single sign on (SSO) is ...

  • Fortinet admits FortiGate SSO bug still exploitable despite December patch

    January 23, 2026

    Fortinet has confirmed that attackers are actively bypassing a December patch for a critical FortiCloud single sign-on (SSO) authentication flaw after customers reported suspicious logins on devices supposedly fully up to date. In a new advisory, Fortinet said it had identified a fresh attack path being used to abuse SAML-based SSO in FortiOS, even on systems ...

  • VMware vCenter Server bug fixed in 2024 under attack today

    January 23, 2026

    You’ve got to keep your software updated. Some unknown miscreants are exploiting a critical VMware vCenter Server bug more than a year after Broadcom patched the flaw. The vulnerability, tracked as CVE-2024-37079, is an out-of-bounds write flaw in vCenter Server’s implementation of the DCERPC protocol that earned a 9.8 out of 10 CVSS rating. In other ...

  • Firefox joins Chrome and Edge as sleeper extensions spy on users

    January 19, 2026

    A group of cybercriminals called DarkSpectre is believed to be behind three campaigns spread by malicious browser extensions: ShadyPanda, GhostPoster, and Zoom Stealer. Malwarebytes Labs wrote about the ShadyPanda campaign in December 2025, warning users that extensions which had behaved normally for years suddenly went rogue. After a malicious update, these extensions were able to track ...