A essential token validation failure in Microsoft Entra ID (beforehand Azure Lively Listing) may have allowed attackers to impersonate any consumer, together with World Directors, throughout any tenant.
The vulnerability, tracked as CVE-2025-55241, has been assigned the utmost CVSS rating of 10.0. It has been described by Microsoft as a privilege escalation flaw in Azure Entra. There isn’t any indication that the problem was exploited within the wild. It has been addressed by the Home windows maker as of July 17, 2025, requiring no buyer motion.
Safety researcher Dirk-jan Mollema, who found and reported the shortcoming on July 14, stated the shortcoming made it attainable to compromise each Entra ID tenant on the planet, with the possible exception of nationwide cloud deployments.
The issue stems from a mixture of two parts: the usage of service-to-service (S2S) actor tokens issued by the Entry Management Service (ACS) and a deadly flaw within the legacy Azure AD Graph API (graph.home windows.internet) that didn’t adequately validate the originating tenant, which successfully allowed the tokens for use for cross-tenant entry.
What makes this noteworthy is that the tokens are topic to Microsoft’s Conditional Entry insurance policies, enabling a foul actor with entry to the Graph API to make unauthorized modifications. To make issues worse, the dearth of API stage logging for the Graph API meant that it may very well be exploited to entry consumer info saved in Entra ID, group and position particulars, tenant settings, utility permissions, and machine info and BitLocker keys synced to Entra ID with out leaving any traces.
An impersonation of the World Administrator may enable an attacker to create new accounts, grant themselves extra permissions, or exfiltrate delicate information, leading to a full tenant compromise with entry to any service that makes use of Entra ID for authentication, equivalent to SharePoint On-line and Trade On-line.
“It could additionally present full entry to any useful resource hosted in Azure, since these sources are managed from the tenant stage and World Admins can grant themselves rights on Azure subscriptions,” Mollema famous.
Microsoft has characterised such situations of cross-tenant entry as a case of “Excessive-privileged entry” (HPA) that “happens when an utility or service obtains broad entry to buyer content material, permitting it to impersonate different customers with out offering any proof of consumer context.”
It is price noting that the Azure AD Graph API has been formally deprecated and retired as of August 31, 2025, with the tech large urging customers emigrate their apps to Microsoft Graph. The preliminary announcement of the deprecation was made in 2019.
“Functions that had been configured for prolonged entry that also rely on Azure AD Graph APIs will be unable to proceed utilizing these APIs beginning in early September 2025,” Microsoft famous again in late June 2025.
Cloud safety firm Mitiga stated a profitable exploitation of CVE-2025-55241 can bypass multi-factor authentication (MFA), Conditional Entry, and logging, leaving no path of the incident.
“Attackers may craft these [actor] tokens in ways in which tricked Entra ID into pondering they had been anybody, wherever,” Mitiga’s Roei Sherman stated. “The vulnerability arose as a result of the legacy API did not validate the tenant supply of the token.”
“This meant that an attacker may get hold of an Actor token from their very own, non-privileged check surroundings after which use it to impersonate a World Admin in another firm’s tenant. The attacker did not want any pre-existing entry to the goal group.”
Beforehand, Mollema additionally detailed a high-severity safety flaw affecting on-premise variations of Trade Server (CVE-2025-53786, CVSS rating: 8.0) that might enable an attacker to achieve elevated privileges below sure circumstances. One other piece of analysis discovered that Intune certificates misconfigurations (equivalent to spoofable identifiers) might be abused by common customers to carry out an ESC1 assault focusing on Lively Listing environments.
The event comes weeks after Binary Safety’s Haakon Holm Gulbrandsrud disclosed that the shared API Supervisor (APIM) occasion used to facilitate software-as-a-service (SaaS) connectors might be invoked straight from the Azure Useful resource Supervisor to realize cross-tenant entry.
“API Connections enable anybody to totally compromise another connection worldwide, giving full entry to the linked backend,” Gulbrandsrud stated. “This contains cross-tenant compromise of Key Vaults and Azure SQL databases, in addition to another externally linked service, equivalent to Jira or Salesforce.”
It additionally follows the invention of a number of cloud-related flaws and assault strategies in current weeks –
- An Entra ID OAuth misconfiguration that granted unauthorized entry to Microsoft’s Engineering Hub Rescue even with a private Microsoft account, exposing 22 inside companies and related information.
- An assault that exploits Microsoft OneDrive for Enterprise Recognized Folder Transfer (KFM) function, permitting a foul actor who compromises a Microsoft 365 consumer with OneDrive sync to achieve entry to their apps and information synced to SharePoint On-line.
- The leak of Azure AD utility credentials in a publicly accessible Utility Settings (appsettings.json) file that might have been exploited to authenticate straight towards Microsoft’s OAuth 2.0 endpoints, and exfiltrate delicate information, deploy malicious apps, or escalate privileges.
- A phishing assault containing a hyperlink to a rogue OAuth utility registered in Microsoft Azure that tricked a consumer into granting it permissions to extract Amazon Net Providers (AWS) entry keys for a sandbox surroundings throughout the compromised mailbox, permitting unknown actors to enumerate AWS permissions and exploit a belief relationship between the sandbox and manufacturing environments to raise privileges, acquire full management over the group’s AWS infrastructure, and exfiltrate delicate information.
- An assault that entails exploiting Server-Aspect Request Forgery (SSRF) vulnerabilities in net purposes to ship requests to the AWS EC2 metadata service with the purpose of accessing the Occasion Metadata Service (IMDS) to compromise cloud sources by retrieving short-term safety credentials assigned to the occasion’s IAM position.
- A now-patched concern in AWS’s Trusted Advisor software that may very well be exploited to sidestep S3 Safety Checks by tweaking sure storage bucket insurance policies, inflicting the software to incorrectly report publicly-exposed S3 buckets as safe, thereby leaving delicate information uncovered to information exfiltration and information breaches.
- A method code AWSDoor that modifies IAM configurations associated to AWS position and belief insurance policies to arrange persistence on AWS environments.
The findings present that even all-too-common misconfigurations in cloud environments can have disastrous penalties for the organizations concerned, resulting in information theft and different follow-on assaults.
“Methods equivalent to AccessKey injection, belief coverage backdooring, and the usage of NotAction insurance policies enable attackers to persist with out deploying malware or triggering alarms,” RiskInsight researchers Yoann Dequeker and Arnaud Petitcol stated in a report printed final week.
“Past IAM, attackers can leverage AWS sources themselves – equivalent to Lambda capabilities and EC2 situations – to take care of entry. Disabling CloudTrail, modifying occasion selectors, deploying lifecycle insurance policies for silent S3 deletion, or detaching accounts from AWS Organizations are all strategies that scale back oversight and allow long-term compromise or destruction.”
