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Recommendations from our Threat Response Unit (TRU) Team:
Indicators of Compromise
References
Adversaries don’t work 9-5 and neither do we. At eSentire, our 24/7 SOCs are staffed with Elite Threat Hunters and Cyber Analysts who hunt, investigate, contain and respond to threats within minutes.
We have discovered some of the most dangerous threats and nation state attacks in our space – including the Kaseya MSP breach and the more_eggs malware.
Our Security Operations Centers are supported with Threat Intelligence, Tactical Threat Response and Advanced Threat Analytics driven by our Threat Response Unit – the TRU team.
In TRU Positives, eSentire’s Threat Response Unit (TRU) provides a summary of a recent threat investigation. We outline how we responded to the confirmed threat and what recommendations we have going forward.
Here’s the latest from our TRU Team…
What did we find?
Our Threat Response Unit (TRU) has observed a surge in AiTM (Adversary in the Middle) phishing attacks. AiTM phishing is a sophisticated tactic where attackers position themselves between the victim and a legitimate website or service. In doing so, they can intercept and often manipulate communications in real-time.
A particularly alarming capability of AiTM phishing is its ability to bypass Multi-Factor Authentication (MFA). Not only can attackers capture real-time MFA tokens or codes, but they can also seize MFA session cookies. With these captured session cookies, attackers can maintain unauthorized access without needing to re-authenticate, effectively sidestepping MFA measures.
This method has become a favored approach for conducting Business Email Compromise (BEC) attacks, where attackers impersonate trusted entities to execute fraudulent activities, including unauthorized financial transactions.
Adversary in the Middle (AiTM) attacks, a variant of the traditional Man-in-the-Middle (MitM) attack, has gained popularity for several reasons:
Effective Bypass of Multi-Factor Authentication (MFA): AiTM attacks allow cybercriminals to intercept real-time data exchanges, including those involving MFA tokens or codes. This ability to capture and potentially use MFA tokens in real time allows attackers to bypass one of the most recommended and widespread security measures.
Capture of Session Cookies: By intercepting communications, attackers can capture session cookies. These cookies can then be used to maintain unauthorized access without needing to re-authenticate, which sidesteps additional security measures.
Trust Exploitation: AiTM attacks are conducted during genuine sessions, which means the victim often feels they are in a legitimate and secure environment. This perceived authenticity makes it easier for attackers to deceive their targets.
Evolution of Attack Tools: The tools and techniques for AiTM attacks have evolved and become more user-friendly. With various Phishing-As-A-Service (PhaaS) tools available nowadays, such as EvilProxy, NakedPages, and DadSec, this means that even attackers with only modest technical skills can launch successful AiTM campaigns.
Cloudflare for Evasion: By incorporating services like Cloudflare's Turnstile tool (CAPTCHA replacement introduced by Cloudflare), attackers can mask the redirect link's true nature. When security tools or researchers attempt to analyze the phishing link automatically, they're met with Turnstile. This not only hinders automated analysis but also adds a layer of perceived legitimacy to the phishing site, as users often associate these tools with legitimate, secure websites.
Figure 1 is an example of an AiTM phishing attack targeting one of our clients. The threat actor(s) impersonated HR personnel and used a QR code to entice the employee into scanning it with their phone. This tactic is especially concerning because it prompts users to enter their credentials on devices that may not be under corporate monitoring.
Figure 1: Example of the AiTM phishing attack leveraging QR code
You can see in Figure 2 that the attacker leveraged Cloudflare Turnstile below to confirm that the visitor is real and to employ the evasion technique mentioned above.
After the successful check, the user is redirected to the fake Microsoft O365 landing page that prompts the user to enter their credentials, as shown in Figure 3.
Figure 3: Fake O365 landing page
Upon entering the valid credentials, the user gets an MFA prompt if it’s set up, as shown in Figure 4.
Figure 4: MFA prompt
When the user confirms their identity using one of the methods, the attacker can intercept and steal the session cookie. This allows them to access the user's account without further authentication, effectively bypassing MFA.
DadSec PhaaS
eSentire TRU has identified the DadSec PhaaS as the orchestrator behind a particular QR code campaign. DadSec offers customers access to a user-friendly phishing panel, enabling them to launch sophisticated phishing attacks easily. This panel allows for theme customization, including antibot features, and more. DadSec promotes its services both on its website and within specific Telegram groups, as depicted in Figure 5. Access to this phishing panel is priced at $500.
Figure 5: DadSec advertisement
We were able to find some evidence of DadSec panel’s source code. All the PHP files are heavily obfuscated (Figure 6).
Figure 6: Obfuscated PHP code
The example of the antibot feature and IP blocking from the deobfuscated code is shown in Figure 7. Whenever it detects one of the bots, crawlers, it displays a “HTTP/1.0 404 Not Found” page.
Figure 7: AntiBot feature
DadSec also displays a “404 Not Found” page on the keywords shown in Figure 8.
Figure 8: Blocked keywords
IP blocking is also in place for IPs such as 65.55.92.152, 216.58.211.37, and so on. We believe that the phishing developer grabbed the keywords, IPs, and bots from the antibot1.php file (MD5: 7db0362ac94539ca92d748bcfff24fdf) shown in Figure 9.
Figure 9: Snippet of antibot1.php file
Figure 10 displays the settings of DadSec. Users can configure it to send results to Telegram or email and set up a redirect URL after credentials are entered. Additionally, there's an option to toggle the Cloudflare Turnstile tool on or off.
In Figure 11, DadSec developer is showcasing the panel and how the custom themed can be set up.
Figure 11: DadSec panel
Figure 12 displays the background images found within the DadSec phishing panel. Recently, Any.Run highlighted in a Twitter post how legitimate services are being exploited for phishing. Notably, one of the screenshots from their post features one of these background images (Figure 13).
After conducting an extensive investigation, we identified over a thousand domains associated with DadSec phishing. Most of these domains are hosted on Cyber Panel, an open-source Web Hosting Control Panel, as illustrated in Figure 14.
To illustrate the mechanics of AiTM and the simplicity of bypassing MFA, we'll deploy Evilginx, a framework tailored for man-in-the-middle phishing attacks.
We will login to the phishing site with our credentials (Figure 15).
Figure 15: O365 phishing landing page
After entering the correct credentials, the user receives an MFA push notification on their phone via the Authenticator app. Upon accepting the sign-in request and choosing to remain logged in, the attacker intercepts the session cookie, which has a limited validity period, as depicted in Figure 16.
Figure 16: The user receiving and approving the MFA push
The attacker obtains the session cookie, which can be entered into the Cookie Editor, allowing them to access the O365 account while circumventing MFA, as illustrated in Figures 17-18.
Figure 18: Successful MFA bypass
What did we do?
Using the Threat Response Unit's Anomalous Login Detection, we successfully identified unusual or risky logins and promptly alerted the affected customers.
What can you learn from this TRU Positive?
AiTM (Adversary in the Middle) is an evolved form of the traditional MitM (Man-in-the-Middle) attacks. It involves attackers positioning themselves between a victim and a legitimate service to intercept and manipulate communications.
One of the most alarming features of AiTM attacks is their ability to effectively bypass Multi-Factor Authentication (MFA) by capturing session cookies. Attackers can seize session cookies during AiTM attacks, allowing them to maintain unauthorized access without re-authentication.
The tools available for conducting AiTM attacks have become more sophisticated and user-friendly. Even individuals with basic technical knowledge can now execute these attacks using services like EvilProxy, NakedPages, and DadSec.
These PhaaS offerings have evolved to capitalize on the latest trends, particularly the use of QR code phishing techniques. As most phishing pages using QR codes are accessed via users' phones, traditional monitoring systems might miss these interactions.
Attackers use services like Cloudflare's Turnstile tool to hide the true nature of redirect links, adding a layer of perceived legitimacy and hindering automated analysis.
Recommendations from our Threat Response Unit (TRU) Team:
Organizations, with eSentire MDR for Log, are strongly recommended to ensure logging is enabled for Azure AD and Office365
Block known malicious indicators via Conditional Access policies by limiting access to trusted IP addresses and locations (see Indicators of Compromise table)
Reduce the lifetime of user sessions.
If impacted by AiTM Phishing:
Reset user credentials.
Revoke active logon sessions.
Review impacted inboxes for rule changes and data exfiltration.
The eSentire Threat Response Unit (TRU) is an industry-leading threat research team committed to helping your organization become more resilient. TRU is an elite team of threat hunters and researchers that supports our 24/7 Security Operations Centers (SOCs), builds threat detection models across the eSentire XDR Cloud Platform, and works as an extension of your security team to continuously improve our Managed Detection and Response service. By providing complete visibility across your attack surface and performing global threat sweeps and proactive hypothesis-driven threat hunts augmented by original threat research, we are laser-focused on defending your organization against known and unknown threats.
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