Exploiting Vulnerabilities in Outlook Web Access (OWA)

Category

Cybersecurity Best Practices

Level

Intermediate

Number

Outlook Web Access (OWA) serves as a web-based email client linked to Microsoft Exchange Server, granting remote access to emails, calendars, and collaborative tools through web browsers.

This system replicates the core functions of the Outlook desktop client, ensuring productivity while on the move.

However, OWA can be exploited by attackers through various methods:

One approach involves exploiting known inconsistencies in response times within OWA, which can be manipulated to gain unauthorized access.
Attackers can also leverage the inefficiency of NTLM over HTTP authentication, a design flaw that can be exploited to compromise security.
Another method is password spraying, where attackers attempt to login with different usernames but the same password, exploiting weak authentication practices.

To carry out these attacks, an attacker typically needs a list of random domain names and a collection of potentially valid domain names, along with access to the domain environment.

Tools like MailSniper on GitHub facilitate these actions, allowing attackers to harvest domain information and potentially breach OWA security.

Summary:

Exploiting vulnerabilities in Outlook Web Access (OWA) involves manipulating response times, NTLM over HTTP flaws, and password spraying
often facilitated by tools like MailSniper for domain harvesting.