How the TameMyCerts Policy Module for Active Directory Certificate Services (ADCS) can detect and prevent attacks against the ESC6 and ESC7 attack vectors

With the supposedly good intention of making it possible to issue such certificate requirements with a SAN, guess unfortunately much at many Instructions  to set the flag on the certification body EDITF_ATTRIBUTESUBJECTALTNAME2 to activate.

If this flag is activated, a very large attack surface is offered, as any applicant can now instruct the certification authority to issue certificates with any content. This type of attack is known in the security scene as ESC6 and ESC7 known.

Continue reading „Wie das TameMyCerts Policy Modul für Active Directory Certificate Services (ADCS) Angriffe gegen die ESC6 und ESC7 Angriffsvektoren erkennen und verhindern kann“

How the TameMyCerts Policy Module for Active Directory Certificate Services (ADCS) can repair incoming certificate requests to make them RFC compliant

Starting with version 58, Google has decided to remove support for the Subject Distinguished Name of web server certificates in the Chrome browser and instead only accept certificates with Subject Alternative Name.

Since this moment, web server certificates without a subject alternative name in the form of a dNSName rejected by Chrome. Other browser manufacturers quickly adopted this approach, meaning that this problem now affects all popular browsers (including Microsoft Edge).

Continue reading „Wie das TameMyCerts Policy Modul für Active Directory Certificate Services (ADCS) eingehende Zertifikatanträge reparieren kann, um sie RFC-konform zu machen“

Change the Subject Alternative Name (SAN) of a certificate before it is issued - but do it securely!

In net circulate unfortunately much at many Instructions (also the big players are not excluded from this, not even Microsoft itself or the Grand Master Komar), which fatally recommend that the flag EDITF_ATTRIBUTESUBJECTALTNAME2 should be set on the certification authority - supposedly to be able to issue certificates with Subject Alternative Name (SAN) extension for manually submitted certificate requests.

Unfortunately, this procedure is not only unnecessary, it also has some unpleasant side effects, which in the worst case can help an attacker to take over the entire Active Directory structure.

Continue reading „Den Subject Alternative Name (SAN) eines Zertifikats vor dessen Ausstellung verändern – aber sicher!“

Active Directory forest compromised by EDITF_ATTRIBUTESUBJECTALTNAME2 flag

In net circulate unfortunately much at many Instructions (also the big players are not excluded from this, not even Microsoft itself or the Grand Master Komar), which fatally recommends that the EDITF_ATTRIBUTESUBJECTALTNAME2 flag should be set on the certification authority - supposedly to be able to issue Subject Alternative Name (SAN) extension certificates for manually submitted certificate requests.

Unfortunately, this approach is not only unnecessary, it also has some unpleasant side effects, which in the worst case can help an attacker to take over the entire Active Directory forest.

Continue reading „Gefährdung der Active Directory Gesamtstruktur durch das Flag EDITF_ATTRIBUTESUBJECTALTNAME2“
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