State-Of-The-Art Phishing: MFA Bypass
Summary:
Cisco Talos investigates why cybercriminals are increasingly bypassing multi-factor authentication (MFA) through adversary-in-the-middle (AiTM) attacks using reverse proxies, allowing them to steal credentials and authentication cookies. This trend is fueled by the availability of Phishing-as-a-Service (PhaaS) kits like Tycoon 2FA and Evilproxy, which receive constant improvements to simplify the execution of these attacks and make them harder to detect. WebAuthn, a passwordless MFA solution based on public key cryptography, offers a strong defense against these attacks by preventing password transmission and rendering server-side authentication databases nullified. However, despite its security benefits, WebAuthn adoption remains low-volume. Cisco Talos aims to ramp up its adoption by advising organizations to reassess their current MFA strategies in light of these evolving phishing kits and the adversaries that employ them, particularly addressing the root causes of easily guessed usernames and weak, reused passwords, which facilitate initial credential compromise and subsequent MFA bypass. The WebAuthn specification was first published back in 2019. According to Cisco Duo authentication telemetry data, WebAuthn MFA authentications still make up a very low percentage of all MFA authentications.
Security Officer Comments:
The evolution of phishing tactics to include sophisticated MFA bypass techniques and the shift to more targeted phishing attacks, such as AiTM attacks facilitated by reverse proxies, presents a serious challenge to traditional security measures. The proliferation of user-friendly PhaaS kits programs has made these advanced attacks accessible to a wider range of cybercriminals. While the slow adoption of WebAuthn understandably may be due to existing MFA deployments and their associated costs, the increasing leveragability of MFA bypass techniques necessitates a shift in defense solutions. Prioritizing the addition of different authentication methods like WebAuthn, which inherently mitigates the risks associated with password-based systems and session cookie theft, may be helpful to organizations. This also emphasizes that a layered security posture that combats phishing in all stages of attacks is critical. This includes enhanced user education on recognizing sophisticated phishing attempts, implementing stronger password policies, and, likely more importantly, deploying security solutions capable of detecting AiTM attack indicators, such as anomalous TLS fingerprints and suspicious authentication activity. Humans will likely always be considered the weakest link in cybersecurity, particularly when it comes to strong password policies. However, organizations can further reduce this significant risk by evolving their defenses when necessary by employing technologies like WebAuthn.
Suggested Corrections:
Users should always be cautious of individuals or organizations that ask for personal information. Most companies will not ask for sensitive data from their customers. If in doubt, users should verify with the company itself to avoid any potential issues.
Users should always take a close look at the sender’s display name when checking the legitimacy of an email. Most companies use a single domain for their URLs and emails, so a message that originates from a different domain is a red flag.
As a general rule, users should not click links or download files even if they come from seemingly “trustworthy” sources.
Check for mismatched URLs. While an embedded URL might seem perfectly valid, hovering above it might show a different web address. In fact, users should avoid clicking links in emails unless they are certain that it is a legitimate link.
Users should always be on the lookout for any grammatical errors and spelling mistakes. Legitimate companies will often employ proofreaders and editors who ensure that the materials they send out are error-free.
Users should not be frightened or intimidated by messages that have an alarmist tone. They should double check with the company if they are uncertain about the status of their accounts.
Phishing emails are designed to be sent to a large number of people, so they need to be as impersonal as possible. Users should check whether the message contains a generic subject and greeting, as this can be a sign of a phishing attempt.
Although not every end user has access to advanced anti-phishing software, they can still use the built-in protection of their email clients to filter messages. One example is setting the email client to block all images unless approved.
Legitimate companies will never send confirmation emails unless there are specific reasons for doing so. In fact, most companies will avoid sending unsolicited messages unless it’s for company updates, newsletters, or advertising purposes.
Users should always take the context of an email or message into account. For example, most online accounts do away with viewable member numbers, so users should be wary if they receive emails containing a “member number” for services that generally don’t use them.
It is important to take note of unusual information in the text of the message. Any mentions of operating systems and software that are not typically used by consumers can often be indicators of a phishing attempt.
If it seems suspicious, it probably is. Users should always err on the side of caution when it comes to sending out personally identifiable information through messages and emails.
Link(s):
https://blog.talosintelligence.com/state-of-the-art-phishing-mfa-bypass/
Cisco Talos investigates why cybercriminals are increasingly bypassing multi-factor authentication (MFA) through adversary-in-the-middle (AiTM) attacks using reverse proxies, allowing them to steal credentials and authentication cookies. This trend is fueled by the availability of Phishing-as-a-Service (PhaaS) kits like Tycoon 2FA and Evilproxy, which receive constant improvements to simplify the execution of these attacks and make them harder to detect. WebAuthn, a passwordless MFA solution based on public key cryptography, offers a strong defense against these attacks by preventing password transmission and rendering server-side authentication databases nullified. However, despite its security benefits, WebAuthn adoption remains low-volume. Cisco Talos aims to ramp up its adoption by advising organizations to reassess their current MFA strategies in light of these evolving phishing kits and the adversaries that employ them, particularly addressing the root causes of easily guessed usernames and weak, reused passwords, which facilitate initial credential compromise and subsequent MFA bypass. The WebAuthn specification was first published back in 2019. According to Cisco Duo authentication telemetry data, WebAuthn MFA authentications still make up a very low percentage of all MFA authentications.
Security Officer Comments:
The evolution of phishing tactics to include sophisticated MFA bypass techniques and the shift to more targeted phishing attacks, such as AiTM attacks facilitated by reverse proxies, presents a serious challenge to traditional security measures. The proliferation of user-friendly PhaaS kits programs has made these advanced attacks accessible to a wider range of cybercriminals. While the slow adoption of WebAuthn understandably may be due to existing MFA deployments and their associated costs, the increasing leveragability of MFA bypass techniques necessitates a shift in defense solutions. Prioritizing the addition of different authentication methods like WebAuthn, which inherently mitigates the risks associated with password-based systems and session cookie theft, may be helpful to organizations. This also emphasizes that a layered security posture that combats phishing in all stages of attacks is critical. This includes enhanced user education on recognizing sophisticated phishing attempts, implementing stronger password policies, and, likely more importantly, deploying security solutions capable of detecting AiTM attack indicators, such as anomalous TLS fingerprints and suspicious authentication activity. Humans will likely always be considered the weakest link in cybersecurity, particularly when it comes to strong password policies. However, organizations can further reduce this significant risk by evolving their defenses when necessary by employing technologies like WebAuthn.
Suggested Corrections:
Users should always be cautious of individuals or organizations that ask for personal information. Most companies will not ask for sensitive data from their customers. If in doubt, users should verify with the company itself to avoid any potential issues.
Users should always take a close look at the sender’s display name when checking the legitimacy of an email. Most companies use a single domain for their URLs and emails, so a message that originates from a different domain is a red flag.
As a general rule, users should not click links or download files even if they come from seemingly “trustworthy” sources.
Check for mismatched URLs. While an embedded URL might seem perfectly valid, hovering above it might show a different web address. In fact, users should avoid clicking links in emails unless they are certain that it is a legitimate link.
Users should always be on the lookout for any grammatical errors and spelling mistakes. Legitimate companies will often employ proofreaders and editors who ensure that the materials they send out are error-free.
Users should not be frightened or intimidated by messages that have an alarmist tone. They should double check with the company if they are uncertain about the status of their accounts.
Phishing emails are designed to be sent to a large number of people, so they need to be as impersonal as possible. Users should check whether the message contains a generic subject and greeting, as this can be a sign of a phishing attempt.
Although not every end user has access to advanced anti-phishing software, they can still use the built-in protection of their email clients to filter messages. One example is setting the email client to block all images unless approved.
Legitimate companies will never send confirmation emails unless there are specific reasons for doing so. In fact, most companies will avoid sending unsolicited messages unless it’s for company updates, newsletters, or advertising purposes.
Users should always take the context of an email or message into account. For example, most online accounts do away with viewable member numbers, so users should be wary if they receive emails containing a “member number” for services that generally don’t use them.
It is important to take note of unusual information in the text of the message. Any mentions of operating systems and software that are not typically used by consumers can often be indicators of a phishing attempt.
If it seems suspicious, it probably is. Users should always err on the side of caution when it comes to sending out personally identifiable information through messages and emails.
Link(s):
https://blog.talosintelligence.com/state-of-the-art-phishing-mfa-bypass/