What We Do
How we do it
Resources
TRU INTELLIGENCE CENTER
Our Threat Response Unit (TRU) publishes security advisories, blogs, reports, industry publications and webinars based on its original research and the insights driven through proactive threat hunts.
View Threat Intelligence Resources →
SECURITY ADVISORIES
Jun 03, 2022
UPDATE: CVE-2022-26134 – Confluence Zero-Day Vulnerability
THE THREAT June 3rd Update: Atlassian has released security patches to address this vulnerability. On June 2nd, 2022, Atlassian disclosed a critical vulnerability impacting the Confluence…
Read More
View all Advisories →
Company
ABOUT ESENTIRE
About Us
eSentire is The Authority in Managed Detection and Response Services, protecting the critical data and applications of 1200+ organizations in 75+ countries from known and unknown cyber threats. Founded in 2001, the company’s mission is to hunt, investigate and stop cyber threats before they become business disrupting events.
Read about how we got here
Leadership Work at eSentire
LATEST PRESS RELEASE
May 17, 2022
Cybersecurity Leader eSentire Continues Its Commitment to Rigorous Security Standards Earning PCI DSS Certification
Waterloo, ON, May 17, 2022 — eSentire, the Authority in Managed Detection and Response (MDR), maintains one of the most secure and robust IT environments of any MDR provider in the industry. To that end, eSentire today announced that it has received the Payment Card Industry Data Security Standard (PCI DSS) certification, considered one of the most stringent and comprehensive payment card…
Read More
Partners
PARTNER PROGRAM
e3 Ecosystem
We provide sophisticated cybersecurity solutions for Managed Security Service Providers (MSSPs), Managed Service Providers (MSPs), and Value-Added Resellers (VARs). Find out why you should partner with eSentire, the Authority in Managed Detection and Response, today.
Learn more
ECOSYSTEM PARTNER RESOURCES
Apply to become an e3 ecosystem partner with eSentire, the Authority in Managed Detection and Response.
Login to the Partner Portal for resources and content for current partners.
Search
Resources
Security advisories — Jul 29, 2021

UPDATE: PetitPotam NTLM Relay Attack

2 minutes read
Speak With A Security Expert Now

THE THREAT

PetitPotam is a variant of the NTLM Relay attack discovered by security researcher Gilles Lionel. It is tracked as an authentication bypass vulnerability in Active Directory (Certificate Services); Microsoft tracks this vulnerability as CVE-2021-36942. Proof of Concept (PoC) code released last week [1] relies on the Encrypting File System Remote (EFSRPC) protocol to provoke a Windows host into performing an NTLM authentication request against an attacker-controlled server, exposing NTLM authentication details or authentication certificates. This information can be used by an attacker to elevate their privileges in a domain environment. Exploitation would require previous access to a vulnerable device.

In response to the release of PetitPotam PoC code, eSentire has deployed new detection content via eSentire's Managed Log service. Microsoft has released mitigations for the attack. Security patches were released on August 10th, 2021. In the wild attacks abusing PetitPotam have not been observed at this time.

What we’re doing about it

UPDATE:

What you should do about it

After performing a business impact review, apply the relevant security patches provided by Microsoft for CVE-2021-36942.

In cases where patching is not possible, Microsoft has released alternative mitigations for this attack [2].

These include:

  1. Disabling NTLM authentication in the environment
  2. Disabling NTLM on Active Directory Certificate Services (AD CS) servers
  3. Enable Extended Protection for Authentication (EPA) on AD CS servers if NTLM cannot be disabled

Detailed mitigation steps are available in the Microsoft Knowledge Base article [2].

Additional information

PetitPotam is a form of NTLM Relay attack which abuses the EFSRPC protocol. In an attack scenario, an attacker with local network access would abuse this protocol to coerce an NTLM authentication request to a server under an attacker’s control. Researchers have successfully relayed NTLM requests, retrieved using PetitPotam to Active Directory Certificate Services (AD CS) servers, to sign a certificate using the relayed NTLM credentials. An attacker can then leverage this signed certificate to elevate their access and compromise the domain. This attack method is described in detail by SANS [3].

Known attack methods abusing PetitPotam require the following conditions to be met:

  1. NTLM Authentication is enabled on your domain
  2. Active Directory Certificate Service is active on your network
  3. Either of the following services are enabled on AD CS:
    1. Certificate Authority Web Enrollment
    2. Certificate Enrollment Web Service

References:

[1] https://github.com/topotam/PetitPotam
[2] https://support.microsoft.com/en-gb/topic/kb5005413-mitigating-ntlm-relay-attacks-on-active-directory-certificate-services-ad-cs-3612b773-4043-4aa9-b23d-b87910cd3429
[3] https://isc.sans.edu/diary/27668 

Join 100,000+ Security Leaders

Get notified when there's a new security advisory, and receive the latest news, intel and helpful tools & assets. You can unsubscribe anytime.

By clicking the button below I confirm that I have read and agree to the eSentire privacy policy.

View Most Recent Blogs