An extensive account takeover (ATO) campaign targeting Microsoft Entra ID has been identified by cybersecurity experts, exploiting a powerful open-source penetration testing framework known as TeamFiltration.
First detected in December 2024, the campaign has accelerated rapidly, compromising more than 80,000 user accounts across many cloud environments over the past several years. It is a sophisticated and stealthy attack operation aimed at breaching enterprise cloud infrastructure that has been identified by the threat intelligence firm Proofpoint with the codename UNK_SneakyStrike, a sophisticated and stealthy attack operation.
UNK_SneakyStrike stands out due to its distinctive operational pattern, which tends to unfold in waves of activity throughout a single cloud environment often targeting a broad spectrum of users. The attacks usually follow a period of silent periods lasting between four and five days following these aggressive bursts of login attempts, a tactic that enables attackers to avoid triggering traditional detection mechanisms while maintaining sustained pressure on organizations' defence systems.
Several technical indicators indicate that the attackers are using TeamFiltration—a sophisticated, open-source penetration testing framework first introduced at the Def Con security conference in 2022—a framework that is highly sophisticated and open source. As well as its original purpose of offering security testing and red teaming services in enterprises, TeamFiltration is now being used by malicious actors to automate large-scale user enumeration, password spraying, and stealthy data exfiltration, all of which are carried out on a massive scale by malicious actors.
To simulate real-world account takeover scenarios in Microsoft cloud environments, this tool has been designed to compromise Microsoft Entra ID, also known as Azure Active Directory, in an attempt to compromise these accounts. It is important to know that TeamFiltration's most dangerous feature is its integration with the Microsoft Teams APIs, along with its use of Amazon Web Services (AWS) cloud infrastructure to rotate the source IP addresses dynamically.
Not only will this strategy allow security teams to evade geofencing and rate-limiting defences, but also make attribution and traffic filtering a significant deal more challenging. Additionally, the framework features advanced functionalities that include the ability to backdoor OneDrive accounts so that attackers can gain prolonged, covert access to compromised systems without triggering immediate alarms, which is the main benefit of this framework.
A combination of these features makes TeamFiltration a useful tool for long-term intrusion campaigns as it enhances an attacker's ability to keep persistence within targeted networks and to siphon sensitive data for extended periods of time. By analysing a series of distinctive digital fingerprints that were discovered during forensic analysis, Proofpoint was able to pinpoint both the TeamFiltration framework and the threat actor dubbed UNK_SneakyStrike as being responsible for this malicious activity.
As a result, there were numerous issues with the tool, including a rarely observed user agent string, hardcoded client identifications for OAuth, and a snapshot of the Secureworks FOCI project embedded within its backend architecture that had been around for quite some time. As a result of these technical artefacts, researchers were able to trace the attack's origin and misuse of tools with a high degree of confidence, enabling them to trace the campaign's origin and tool misuse with greater certainty.
An in-depth investigation of the attack revealed that the attackers were obfuscating and circumventing geo-based blocking mechanisms by using Amazon Web Services (AWS) infrastructure spanning multiple international regions in order to conceal their real location. A particularly stealthy manoeuvre was used by the threat actors when they interacted with the Microsoft Teams API using a "sacrificial" Microsoft Office 365 Business Basic account, which gave them the opportunity to conduct covert account enumeration activities.
Through this tactic, they were able to verify existing Entra ID accounts without triggering security alerts, thereby silently creating a map of user credentials that were available. As a result of the analysis of network telemetry, the majority of malicious traffic originated in the United States (42%). Additional significant activity was traced to Ireland (11%) and the United Kingdom (8%) as well. As a consequence of the global distribution of attack sources, attribution became even more complex and time-consuming, compromising the ability to respond efficiently.
A detailed advisory issued by Proofpoint, in response to the campaign, urged organisations, particularly those that rely on Microsoft Entra ID for cloud identity management and remote access-to initiate immediate mitigations or improvements to the system. As part of its recommendations, the TeamFiltration-specific user-agent strings should be flagged by detection rules, and multi-factor authentication (MFA) should be enforced uniformly across all user roles, based on all IP addresses that are listed in the published indicators of compromise (IOCs).
It is also recommended that organisations comply with OAuth 2.0 security standards and implement granular conditional access policies within Entra ID environments to limit potential exposure to hackers. There has been no official security bulletin issued by Microsoft concerning this specific threat, but internal reports have revealed that multiple instances of unauthorised access involving enterprise accounts have been reported. This incident serves as a reminder of the risks associated with dual-use red-teaming tools such as TeamFiltration, which can pose a serious risk to organisations.
There is no doubt in my mind that such frameworks are designed to provide legitimate security assessments, however, as they are made available to the general public, they continue to raise concerns as they make it more easy for threat actors to use them to gain an advantage, blurring the line between offensive research and actual attack vectors as threats evolve.
The attackers during the incident exploited the infrastructure of Amazon Web Services (AWS), but Amazon Web Services (AWS) reiterated its strong commitment to promoting responsible and lawful use of its cloud platform. As stated by Amazon Web Services, in order to use its resources lawfully and legally, all customers are required to adhere to all applicable laws and to adhere to the platform's terms of service.
A spokesperson for Amazon Web Services explained that the company maintains a clearly defined policy framework that prevents misappropriation of its infrastructure. As soon as a company receives credible reports that indicate a potential violation of these policies, it initiates an internal investigation and takes appropriate action, such as disabling access to content that is deemed to be violating the company's terms. As part of this commitment, Amazon Web Services actively supports and values the global community of security researchers.
Using the UNK_SneakyStrike codename, the campaign has been classified as a highly orchestrated and large-scale operation that is based on the enumeration of users and password spraying. According to researchers at Proofpoint, these attempts to gain access to cloud computing services usually take place in bursts that are intense and short-lived, resulting in a flood of credentials-based login requests to cloud environments. Then, there is a period of quietness lasting between four and five days after these attacks, which is an intentional way to prevent continuous detection and prolong the life cycle of the campaign while enabling threat actors to remain evasive.
A key concern with this operation is the precision with which it targets its targets, which makes it particularly concerning. In the opinion of Proofpoint, attackers are trying to gain access to nearly all user accounts within the small cloud tenants, while selectively targeting particular users within the larger enterprise environments.
TeamFiltration's built-in filtering capabilities, which allow attackers to prioritise the highest value accounts while avoiding detection by excessive probing, are a calculated approach that mirrors the built-in filtering capabilities of TeamFiltration. This situation underscores one of the major challenges the cybersecurity community faces today: tools like TeamFiltration that were designed to help defenders simulate real-world attacks are increasingly being turned against organisations, instead of helping them fight back.
By weaponizing these tools, threat actors can infiltrate cloud infrastructure, extract sensitive data, establish long-term access, and bypass conventional security controls, while infiltrating it, extracting sensitive data, and establishing long-term control. In this campaign, we are reminded that dual-purpose cybersecurity technologies, though essential for improving organization resilience, can also pose a persistent and evolving threat when misappropriated.
As the UNK_SneakyStrike campaign demonstrates, the modern threat landscape continues to grow in size and sophistication, which is why it is imperative that cloud security be taken into account in a proactive, intelligence-driven way. Cloud-native organisations must take steps to enhance their threat detection capabilities and go beyond just reactive measures by investing in continuous threat monitoring, behavioural analytics, and threat hunting capabilities tailored to match their environments' needs.
In the present day, security strategies must adapt to the dynamic nature of cloud infrastructure and the growing threat of identity-based attacks, which means relying on traditional perimeter defences or static access controls will no longer be sufficient. In order to maintain security, enterprise defenders need to routinely audit their identity and access management policies, verify that integrated third-party applications are secure, and review logs for anomalies indicative of low-and-slow intrusion patterns.
In order to build a resilient ecosystem that can withstand emerging threats, cloud service providers, vendors, and enterprise security teams need to work together in order to create a collaborative ecosystem. As an added note, cybersecurity community members must engage in ongoing discussions about how dual-purpose security tools should be distributed and governed to ensure that innovation intended to strengthen defences is not merely a weapon that compromises them, but rather a means of strengthening those defences.
The ability to deal with advanced threats requires agility, visibility, and collaboration in order for organisations to remain resilient. There is no doubt that organisations are more vulnerable to attacks than they were in the past, but they can minimise exposure, contain intrusions quickly, and ensure business continuity despite increasingly coordinated, deceptive attack campaigns if they are making use of holistic security hygiene and adopting a zero-trust architecture.
Tech titan Microsoft has emerged as an unexpected yet potent competitor in the cybersecurity industry in a time of rapid digital transformation and rising cyber threats. The company has quickly evolved from its conventional position to become a cybersecurity juggernaut, meeting the urgent demands of both consumers and enterprises in terms of digital security thanks to its broad suite of software and cloud services.
Microsoft entered the field of cybersecurity gradually and strategically. A whopping $20 billion in security-related revenue has been produced by the corporation, according to recent reports, underlining its dedication to protecting its clients from an increasingly complicated cyber scenario. This unexpected change was brought on by many strategic acquisitions and a paradigm shift that prioritized security in all of its services.
The business has considerably improved its capacity to deliver cutting-edge threat information and improved security solutions as a result of its acquisition of cybersecurity businesses like RiskIQ and ReFirm Labs. Microsoft has been able to offer a comprehensive package of services that cover threat detection, prevention, and response by incorporating these cutting-edge technologies into its current portfolio.
The Azure cloud platform is one of the main factors contributing to Microsoft's success in the cybersecurity industry. As more companies move their operations to the cloud, it is crucial to protect the cloud infrastructure. Azure has been used by Microsoft to provide strong security solutions that protect networks, programs, and data. For instance, its Azure Sentinel service uses machine learning and artificial intelligence to analyze enormous volumes of data and find anomalies that could point to possible security breaches.
Furthermore, Microsoft's commitment to addressing cybersecurity issues goes beyond its own products. The business has taken the initiative to work with the larger cybersecurity community in order to exchange threat intelligence and best practices. Its participation in efforts like the Cybersecurity Tech Accord, which combines international tech companies to safeguard clients from cyber dangers, is an example of this collaborative approach.
Microsoft's success in the field of cybersecurity is not without its difficulties, though. The broader cybersecurity sector continues to be beset by a chronic spending issue as it works to strengthen digital defenses. Microsoft makes large investments in security, but many other companies find it difficult to set aside enough funding to properly combat attacks that are always developing.
This is not the first time Microsoft has faced criticism for its security practices. In the past, the company has been accused of failing to protect user data adequately and of not being transparent about data breaches. In this case, Yoran claims that Microsoft needs to be more forthcoming about the extent of the vulnerabilities present in the Azure platform.
The implications of these allegations are profound. If true, it would mean that Microsoft has knowingly put its customers at risk by failing to disclose vulnerabilities in its platform. This could expose sensitive data to hackers and other malicious actors, putting individuals and organizations at risk.
It is important to note that these allegations have not been proven and that Microsoft has not yet responded. However, if authentic, it would represent a significant breach of trust between Microsoft and its customers. Companies rely on cloud platforms like Azure to store and manage their data, and they expect these platforms to be secure and transparent about any potential risks.
In light of these allegations, it is essential for companies to evaluate their use of cloud platforms carefully and to ensure that they are taking appropriate measures to protect their data. This may include using additional security measures such as encryption and multi-factor authentication and regularly reviewing their cloud provider’s security practices.
The recent allegations against Microsoft regarding its security practices and the Azure platform are concerning. If true, they represent a significant breach of trust between Microsoft and its customers. It is essential for companies to evaluate their use of cloud platforms carefully and to take appropriate measures to protect their data.
Microsoft has taken a big step to strengthen the security of its products in response to the growing cybersecurity threats and a number of recent high-profile attacks. The business has declared that it will offer all users essential security features at no cost. Microsoft is making this change in an effort to allay concerns about the security of its platforms and shield its users from potential cyberattacks.
The Messenger, The Register, and Bloomberg all reported that Microsoft made the decision to offer these security capabilities free of charge in response to mounting demand to improve security across its whole portfolio of products. Recent cyberattacks have brought up important issues with data privacy and information security, necessitating the development of stronger protection methods.
A number of allegedly state-sponsored hacks, with China as a particular target, are one of the main drivers behind this tactical approach. Governments, corporations, and individual users all over the world are extremely concerned about these breaches since they target not only crucial infrastructure but also important data.
Improved encryption tools, multi-factor authentication, and cutting-edge threat detection capabilities are among the free security improvements. Users of Microsoft's operating systems, including Windows 10 and Windows 11, as well as cloud-based services like Microsoft 365 and Azure, will have access to these functionalities. Microsoft wants to make these crucial security features available to a broader variety of customers, independent of subscription plans, by removing the financial barrier.
Microsoft responded to the judgment by saying, "We take the security of our customers' data and their privacy extremely seriously. We think it is our duty to provide our users with the best defenses possible as threats continue to evolve. We believe that by making these security features available for free, more people will take advantage of them and improve their overall cybersecurity posture.
Industry professionals applaud Microsoft for choosing to offer these security measures without charge. This is a huge step in the right direction, said Mark Thompson, a cybersecurity analyst with TechDefend. Because these services are free, Microsoft is enabling its users to properly defend themselves against possible attacks as cyber threats become more complex.
The action is also in line with the work of other cybersecurity organizations, including the Cybersecurity and Infrastructure Security Agency (CISA), which has been promoting improved cooperation amongst IT businesses to battle cyber threats.
Although the choice definitely benefits customers, it also poses a challenge for other digital firms in the sector. Customers are expected to demand comparable initiatives from other big players in response to the growing emphasis on data security and privacy, driving the entire sector toward a more secure future.
Descope researchers have labeled the attack as “nOAuth”. The campaign, according to them is an authentication implementation flaw that affects multitenant OAuth apps in Azure AD, Microsoft's cloud-based identity and access management service. If the attack is successful, the threat actor could then take over their victim’s accounts, enabling them to create persistence, exfiltrate data, determine whether lateral movement is feasible, and other activities.
According to Omer Cohen, CISO at Descope ”OAuth and OpenID Connect are open, popular standards which millions of Web properties already use[…]If 'Log in with Microsoft' is improperly implemented, several of these apps could be vulnerable to account takeover. Small businesses with fewer developer resources could especially be impacted.”
OAuth is an open source, token-based authorization framework that enables users to log into applications automatically based on prior authentication to another reputable app. Most consumers are already familiar with this thanks to the "Log in with Facebook" or "Log in with Google" choices seen on numerous e-commerce websites.
OAuth is used in the Azure AD environment to control user access to outside resources including Microsoft 365, the Azure portal, and thousands of other SaaS applications that support OAuth apps.
According to Descope analysis "Azure Active Directory also manages internal resources like apps on your corporate intranet and any cloud apps developed by your own organization by providing authentications via OAuth, OIDC, and other standard protocols."
As per an issue of Descope analysis, published this week, the flaw allows malicious actors to do cross-platform spoofing by only needing an unknowing victim's email address to mimic them. The email attribute under "Contact Information" in an Azure AD account can therefore be changed at will to control the email authentication claim by anyone with malicious intent and a reasonable level of platform expertise.
"[This] allows the attacker to use 'Log in with Microsoft' with the email address of any victim they want to impersonate[…]They can take over victims' accounts on any app that uses 'email' claim as the unique identifier for Microsoft OAuth and does not validate that email address, completely bypassing authentication," the researchers noted.
Incorrect implementation of OAuth has apparently turned into a business, urging organizations to shut down this potentially harmful attack vector.
Some recent cases of the attack include vulnerabilities in the authorization system of the Booking.com website. The attack could have allowed attackers to access user accounts and acquire their personal or payment-card data, as well as log in to accounts on the website's sister platform, Kayak.com.
Another case came to highlight when a bug, tracked as CVE-2023-28131 was discovered in the OAuth implementation of Expo, an open-source framework for developing native mobile apps for iOS, Android, and other Web platforms which was apparently utilizing a single codebase. This vulnerability was the reason why online users were at risk, those who logged in to an online service that employs the framework using different social media accounts.
Cohen notes that the OAuth standard and other such standards are reliable and strong authentication approaches. However, organizations must ensure to collaborate with cybersecurity and authentication professionals when adopting them.
"These standards are extremely complicated to work with[…]Authentication isn’t something you can just add on and check a box. Implementing these standards correctly is critical to the security of the application," says Cohen. He adds, "If businesses chose to implement these standards in-house, then they must have regular pen testing and review of the implementation, or they can use an authentication platform that is built by security experts".
Moreover, he emphasized its importance, since threat actors are constantly on a lookout for these types of vulnerabilities.
Microsoft recently announced that WAF (Web Application Firewall) bot safety tool has attained general availability status on Azure Application Gateway from this week. Azure WAF is a cloud based feature built to safeguard client web applications from bot attacks, general web vulnerabilities and common exploits, including SQL injection, cross site scripting, security misconfigurations, and broken authority and more. Azure WAF can be planted within minutes with Azure Application gateway, Azure Content Delivery Network (CDN) and Azure front door. Microsoft on Friday said that it is announcing the general availability of the Web Application Firewall (WAF) bot protection feature on Application Gateway.
The feature lets customers to control bot protection rule set for WAF to log requests or restrict them from known harmful IP addresses. "Roughly 20% of all Internet traffic comes from bad bots. They do things like scraping, scanning, and looking for vulnerabilities in your web application. When these bots are stopped at the Web Application Firewall (WAF), they can’t attack you. They also can’t use up your resources and services, such as your backends and other underlying infrastructure," reports Microsoft.
The new bot protection rule can be used with OWASP CRS (Core Rules Set) to give extra safety for web applications. Because of this new rule that blocks bad bots, criminals can usi ot for different malicious tasks which are resource consuming like scanning, scraping, and looking out for exploits in web apps. When the bot protection rule is implemented on Azure WAF via Application Gateway, bots that use known malicious IPs retrieved from Microsoft Threat Intelligence feed are get automatically restricted from accessing customer server resources or verifying them on potential vulnerability gaps. "The bot mitigation ruleset list of known bad IP addresses updates multiple times per day from the Microsoft Threat Intelligence feed to stay in sync with the bots," Microsoft said.
"Your web applications are continuously protected even as the bot attack vectors change," reports Bleeping Computers. You can get more information on WAF on Microsoft's Azure Product Website. Bleeping Computers reports "the steps required to configure a bot protection rule set include: Creating a basic WAF policy for Application Gateway by following the instructions described in Create Web Application Firewall policies for Application Gateway. In the Basic policy page that you created previously, under Settings, select Rules. On the details page, under the Manage rules section, from the drop-down menu, select the check box for the bot Protection rule, and then select Save."