How Hackers Exploit Active Directory Certificate Services for Long-Term Persistence

Introduction

Active Directory Certificate Services (AD CS) may seem like a helpful gatekeeper for managing digital certificates and encryption, but if it’s not configured just right, it can leave the door wide open for hackers. AD CS is often overlooked when it comes to security, making it a perfect treasure trove for attackers. And once they’re in, they can sneak around undetected, establishing long-term persistence in your network like they’re on an extended vacation.

Meme :  AD Certificate Services
Credit: Medium

In this blog, we’ll break down how hackers exploit AD CS, dive into some clever tactics from recent findings, and most importantly, explain what you can do to keep them out.

Hackers in the Shadows: How AD CS Is Exploited

AD CS is Microsoft’s Public Key Infrastructure (PKI) solution for issuing and managing digital certificates in Active Directory environments. When configured correctly, it helps secure network communications. But if misconfigured, AD CS can quickly become a hacker’s best friend, enabling them to access networks, steal credentials, and stay hidden for the long haul.

Key Attack Vectors

  1. Stealing Certificates: Imitation is the Best (Criminal) Strategy
    Hackers can grab user or machine certificates, along with private keys, and use them to impersonate legitimate users or machines. This is like copying someone’s ID, if the certificate remains valid, they can continue authenticating, even after passwords change.
  2. Requesting Fake Certificates: Elevation Without the Effort
    Imagine asking for a regular office key but getting access to the CEO’s office instead. Similarly, if there are any misconfigured certificate templates, low-privileged users can request certificates that grant admin-like privileges.
  3. Misconfigured Certificate Templates: Unintentional Free Pass
    Certificate templates can be dangerous when they allow attackers to specify Subject Alternative Names (SANs). This essentially hands over the keys to high-level users’ certificates—like getting access to a domain admin’s credentials. Templates that aren’t secured give attackers serious access.
  4. CA Private Key Theft: A Permanent Invitation
    If an attacker can get their hands on a Certificate Authority (CA) private key, they can generate certificates for any user in the domain. This grants them persistent access that’s nearly impossible to revoke.
  5. Become a Shadow CA
    If an attacker can get a certificate signing request (CSR) signed by CA, which has constraint isCA is set to True, and allowed its use for signing other certificates, then the issue\d certificate makes the attacker a Parallel CA, which can independently generate any arbitrary certificates which will be considered as valid.
How to exploit AD Certificate Services

Tools of the Trade: Certify and ForgeCert

Hackers aren’t going in blind—they’ve got tools that make exploiting AD CS a breeze. The whitepaper by Will Schroeder and Lee Christensen highlights two key tools:

  • Certify: This tool scans for AD CS misconfigurations and assists attackers in requesting malicious certificates. It functions like a vulnerability scanner specifically designed for certificates.
  • ForgeCert: Attackers use this tool to create fake certificates with a stolen CA private key. By forging these certificates, they gain permanent access to your network, making detection much more challenging.
 Certify tool to exploit AD Certificate Services

Mitigation: Fortify Your AD CS Before It’s Too Late

So, how can companies stop attackers from abusing AD CS? It’s all about treating your certificates like they’re gold and your CAs like they’re Fort Knox. Here’s a breakdown of what you need to do:

  1. Treat CAs as Critical Assets
    Your CA servers should be protected like domain controllers (or fort knox), lock them down and apply Tier 0 security controls. These systems are high-value targets, and attackers know it.
  2. Audit and Harden Certificate Templates
    Regularly audit your certificate templates and remove any unnecessary features, like SAN customization, which could give attackers an easy way in. Ensure templates are configured for minimum privilege.
  3. Secure CA Private Keys
    Store CA private keys in hardware security modules (HSMs). This keeps them away from prying hands and makes it significantly harder for attackers to steal them.
  4. Monitor Certificate Activity
    Keep an eye on your certificate enrolments, authentications, and template modifications. If something seems off, it probably is. Proactive monitoring can be your early warning system.

Conclusion

Active Directory Certificate Services isn’t inherently insecure, but its complexity makes it ripe for misconfiguration. When that happens, hackers can sneak in, steal credentials, and establish persistence that’s incredibly tough to detect and eliminate. As the Certified Pre-Owned whitepaper highlights, understanding the risks and securing AD CS is key to preventing these kinds of attacks.

To learn more about Secure usage & management of X509 Certificates, you can refer to this in depth Practitioners Guide authored by our founder Ajit Hatti as part of Null Cipher Security Club

In short, if you’re not securing AD CS, hackers might just settle in and stick around your network for longer than you’d like.

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Certified Pre-Owned: Abusing Active Directory Certificate Services

Microsoft Entra ID Vulnerabilities: Pass-Through Authentication Risks

Microsoft Reveals Russian Hack: Executives’ Emails Compromised

Secure Usage & Management of X509 Certificate

Microsoft Entra ID Vulnerabilities: Pass-Through Authentication Risks

Introduction to Microsoft Entra ID and Pass-Through Authentication

Microsoft Entra ID, previously known as Azure Active Directory (Azure AD), provides a unified identity management solution for both on-premises and cloud-based applications. One key feature of Entra ID Pass-Through Authentication (PTA), which allows users to sign in using the same password for both environments. This setup aims to enhance user experience and reduce IT support costs.

How Pass-Through Authentication Works

In PTA, the system validates users’ passwords against the on-premises Active Directory (AD) instead of storing them in the cloud. When a user tries to log in, Azure AD redirects them, and they enter their credentials. The system encrypts these credentials and sends them to a queue. An on-premises PTA agent retrieves the credentials from the queue, decrypts them, and checks them against the on-prem AD. The agent then sends the result back to Azure AD to complete the login process.

Microsoft Entra ID vulnerabilities: How PTA Works
Credit – Cymulate

Recent Vulnerabilities and Exploits

A recent vulnerability has exposed critical flaws in Microsoft Entra ID’s PTA mechanism. Researchers have discovered that attackers with local administrative privileges on a PTA agent can bypass authentication controls. This flaw allows attackers to impersonate any synchronised user without knowing their actual password.

This vulnerability effectively turns the PTA agent into a “Double Agent,” granting unauthorised access to any user account, including those with elevated privileges. If exploited, attackers could potentially gain full network privileges across the enterprise, posing significant risks.

Attack Methods and Implications

  1. Compromising the PTA Agent: Attackers who gain administrative access to the PTA agent can use tools to install a backdoor. This backdoor enables the attacker to authenticate as any user and even retrieve passwords in clear text.
  2. Seamless SSO Vulnerabilities: Seamless Single Sign-On (SSO) can also be used in coexistence with PTA, which introduces additional risks. Exploiting these vulnerabilities can further compromise an organisation’s security.
  3. Lateral Movement: Once inside the network, attackers can exploit the PTA vulnerability to move laterally across different domains and departments, increasing the scope of the attack.

Mitigation Strategies

To mitigate these risks, Microsoft suggested treating the Entra Connect server as a Tier 0 component, along with hardening the Microsoft Entra Connect server as a Control Plane asset.

Additionally, organizations should implement several key security measures:

  • Restrict Access: Limit access to PTA agent servers to prevent unauthorised modifications.
  • Robust Password Policies: Enforce strong password policies to enhance security.
  • Multi-Factor Authentication (MFA): Require MFA to add an additional layer of security and prevent lateral movement.
  • Monitor Authentication Logs: Implement encrypted authentication logs with detection alerts to identify and respond to potential breaches quickly.

Secure Authentication with PureAUTH

Time and again we have seen Microsoft and other traditional IAM solution providers rely on passwords & fail to provide secure authentication across cloud and on premise environments.

For more secure & reliable authentication, enterprises can depend on PureAUTH IAM firewall which protects enterprises from all credential based attacks and such 0 day vulnerabilities.

Conclusion

The Microsoft Entra ID vulnerability highlights the importance of securing authentication mechanisms and understanding potential weaknesses in identity management systems. With the constantly changing best practices implementing secure authentication is difficult. Organisations must constantly work to protect themselves from such threats.

For more details, refer to the Cymulate blog post and Microsoft’s official security advisories.

Passwords Leaked : Microsoft in Trouble

Introduction

Recent reports unveil a significant data breach at Microsoft, exposing employee passwords and confidential corporate data to the internet. This breach underscores the pressing need for robust cybersecurity protocols and heightened vigilance to safeguard sensitive information.

About the Breach

Security researchers from SOCRadar (Can Yoleri, Murat Özfidan and Egemen Koçhisarlı )discovered an open and public storage server on Microsoft’s Azure cloud service. This server was housing internal data related to the Bing search engine. Left unprotected, it exposed code, scripts, and configuration files containing credentials used by Microsoft employees to access internal systems.

Data Exposure

The exposed data poses severe risks, potentially granting malicious actors access to other confidential files within Microsoft’s network. The lack of password protection on the server facilitated easy access to sensitive information, raising concerns about cybersecurity vulnerabilities.

Response and Resolution

The researchers promptly notified Microsoft of the vulnerability in February, prompting the company to secure the exposed server by March. However, the duration of the data exposure and the extent of unauthorised access remain unclear.

In a statement shared after publication on 10th April, Microsoft’s Jeff Jones said: “Though the credentials should not have been exposed, they were temporary, accessible only from internal networks, and disabled after testing. We thank our partners for responsibly reporting this issue.” But Microsoft has yet to issue an official statement addressing the breach.

Breach History: The latest addition to a series of “Mishaps”


Microsoft has faced numerous security breaches, like the ‘Summer 2023 Exchange Intrusion,’ where hackers accessed mailboxes of 22 organizations and 500 individuals, including senior US government officials. The company’s lax corporate culture and failure to prioritise security investments were criticised by the US Cyber Safety Review Board. Recent oversights, like mislabelling CVEs in Patch Tuesday releases, exposed gaps in Microsoft’s security protocols. Last year, researchers found that Microsoft employees were exposing their own corporate network logins in code published to GitHub.

Conclusion

As Microsoft grapples with the aftermath of this data breach, it highlights the ongoing battle against evolving cybersecurity threats. Human error is inevitable, and we require systems that are error-proof to avoid such breaches occurring in the future. By embracing secure identity and access management technologies, such as passwordless authentication, organizations can significantly reduce the risk of security lapses and enhance overall cybersecurity posture.

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Securing Cloud Environments: Lessons from the Microsoft Azure Breach

Securing Cloud Environments: Lessons from the Microsoft Azure Breach

Introduction

In the wake of the recent Microsoft Azure breach, it has become increasingly evident that organizations must prioritise enhancing their security posture to mitigate the risk of similar incidents in the future. This breach, attributed to compromised passwords & MFA manipulation, underscores the critical importance of implementing passwordless authentication solutions to strengthen overall security.

The Breach

The breach unfolded through a series of sophisticated maneuvers executed by cyber criminals to exploit weaknesses in Azure’s security framework. Initially, phishing emails targeted mid and senior-level executives, enticing them into disclosing their login credentials unwittingly. 

Armed with these credentials, attackers gained unauthorised access to Azure accounts, despite the presence of multi-factor authentication (MFA). By circumventing MFA and substituting victims’ MFA settings with their own, attackers maintained undetected access to Azure resources. 

They further obscured their identities using proxies, evading detection while seizing control of sensitive data and cloud resources.

This helps attackers bypass any poorly designed adaptive authentication solution relying on IP based access restriction or re-authentication.

How Microsoft Azure was Breached

The Lessons

  1. Phishing: Implement Phishing-Resistant Authentication Methods
    • Organisations must adopt phishing-resistant authentication methods to combat prevalent phishing attacks. Staff training alone may not suffice, necessitating solutions that minimise the risk of credential theft.
  2. Credential Theft: Go Passwordless
    • Enhanced credential security with multi-factor authentication is insufficient. Robust password management practices and adaptive MFA solutions have been and will continue to be breached unless you eliminate credentials altogether. Passwordless solutions are the optimal choice for enterprises, as they have been for quiet some time now. Both enterprises and individuals must recognise and adopt it as a standard practice.
  3. MFA Replacement: Implement Continuous Monitoring and Anomaly Detection
    • When you’re using credentials, it’s crucial to keep an eye on them. Continuous monitoring and anomaly detection play a vital role here. They help spot any unauthorised changes in MFA settings promptly, preventing any further access.
  4. Masking Location Using Proxies: Strengthen Adaptive Authentication Checks
    • Strengthening adaptive authentication checks is vital to detect suspicious activities like masked locations. Geo-location based authentication or behavioural biometrics can enhance authentication accuracy.
  5. Cloud Account Takeover: Implement Zero Trust Security Architecture
    • Implementing a Zero-trust security model is crucial to verify every access request, regardless of source or location. Granular access controls and continuous monitoring can mitigate the impact of cloud account takeovers.

Moving Forward

In the aftermath of this breach, organizations must prioritise fortifying their security posture to prevent similar incidents. While passwordless authentication solutions offer promising alternatives, organizations should also concentrate on strengthening existing security protocols, conducting regular security audits, and enhancing employee awareness to mitigate future threats effectively.

Conclusion

The breach of Microsoft Azure serves as a stark reminder of the imperative for proactive cybersecurity measures in safeguarding sensitive data and mitigating the risk of unauthorised access. 

By embracing passwordless authentication solutions and implementing a holistic security strategy, organizations can enhance their resilience against evolving cyber threats and safeguard their invaluable assets effectively.

Microsoft Reveals Russian Hack: Executives’ Emails Compromised

Introduction

In a recent disclosure, Microsoft unveils the details of a sophisticated cyber breach by Russian state-sponsored hackers. The breach, detected on January 12, sheds light on the tactics of the notorious hacking group, Midnight Blizzard, also known as APT29 or Cozy Bear.

Breach Overview: Understanding the Intrusion

In November 2023, Midnight Blizzard initiated a password spray attack. They compromised a legacy non-production test tenant account, gaining access to limited Microsoft email accounts.

Compromised Accounts: Impact on Corporate Email Security

The aftermath reveals that a select group fell victim, including members of Microsoft’s senior leadership team and employees in crucial functions such as cybersecurity and legal. The attackers exfiltrated emails and attached documents, putting sensitive information at risk.

Attribution and Interest: Identifying the Culprits

Microsoft’s threat research team attributed the breach to APT29, emphasising the group’s specific interest in Microsoft’s knowledge of their operations. This marks Midnight Blizzard’s return after their infamous 2020 cyberattack on SolarWinds.


Highlighting the Key Issue: Addressing Problems with Passwords

The breach underscores the vulnerability posed by traditional password systems. The password spray attack exploited weak passwords, showcasing the critical need for organizations to evolve towards passwordless solutions to enforce security.

Risk Mitigation: Addressing Future Threats

Microsoft, quick to respond, is now advocating for the adoption of passwordless solutions as a preventive measure against such breaches. The urgency to reassess and enhance cybersecurity measures has never been more evident.

Immediate Response: Microsoft’s Swift Action

In response to the breach, Microsoft has promptly applied enhanced security standards to its legacy systems and internal business processes. This immediate action aims to sabotage potential follow-up attacks and protect against further unauthorised access.

Ongoing Investigation: Collaborating with Authorities

The investigation is ongoing, with Microsoft actively collaborating with law enforcement and regulators to comprehensively assess the full impact of the breach. This collaboration is crucial for determining additional preventive measures and addressing the evolving landscape of cyber threats.

Conclusion: Looking Ahead

As companies face ever-changing online risks, the Microsoft hack is a clear signal that using weak passwords can be a big problem. Implementing passwordless solutions stands out as a critical step towards a more secure digital future.