CVE-2019-1084 : Exploit Details and Defense Strategies

A vulnerability in Microsoft Exchange Server allows the creation of entities with non-printable characters in their Display Names, enabling authenticated attackers to exploit this issue. This CVE is also known as the 'Microsoft Exchange Information Disclosure Vulnerability'.

Understanding CVE-2019-1084

This CVE involves an information disclosure vulnerability in Microsoft Exchange that affects various Microsoft products.

What is CVE-2019-1084?

This vulnerability in Exchange permits the creation of entities with non-printable characters in their Display Names. Attackers with authentication can leverage this flaw by creating entities with invalid display names that remain hidden in conversations.

The Impact of CVE-2019-1084

The vulnerability poses a risk of information disclosure as attackers can manipulate display names to conceal entities within conversations, potentially leading to unauthorized access to sensitive information.

Technical Details of CVE-2019-1084

This section provides detailed technical insights into the vulnerability.

Vulnerability Description

The vulnerability allows the creation of entities with non-printable characters in Display Names, enabling attackers to hide malicious entities in conversations.

Affected Systems and Versions

Microsoft Exchange Server 2010 Service Pack 3
Microsoft Outlook 2010 Service Pack 2 (32-bit and 64-bit editions), 2016 (32-bit and 64-bit editions), 2013 Service Pack 1 (32-bit and 64-bit editions)
Microsoft Office 2013 Service Pack 1 (32-bit and 64-bit editions), 2013 RT Service Pack 1, 2016 for Mac, 2016 (32-bit and 64-bit editions), 2019 for 32-bit and 64-bit editions, 2019 for Mac
Microsoft Lync 2013 Service Pack 1 (32-bit and 64-bit), Microsoft Lync Basic 2013 Service Pack 1 (32-bit and 64-bit)
Microsoft Outlook for Android, Skype for Business 2016 (32-bit and 64-bit), Skype for Business Basic 2016 (32-bit and 64-bit), Office 365 ProPlus (32-bit and 64-bit Systems)
Microsoft Exchange Server 2016 Cumulative Update 12 and 13, Microsoft Exchange Server 2019 Cumulative Update 1 and 2, Microsoft Exchange Server 2013 Cumulative Update 23, Mail and Calendar, Outlook for iOS

Exploitation Mechanism

The vulnerability can be exploited by authenticated attackers to create entities with invalid display names, which can be used to hide malicious content within conversations.

Mitigation and Prevention

Protecting systems from CVE-2019-1084 requires immediate actions and long-term security practices.

Immediate Steps to Take

Apply the security update released by Microsoft to validate display names during creation in Microsoft Exchange.
Ensure that invalid display names are rendered correctly in Microsoft Outlook clients.

Long-Term Security Practices

Regularly update and patch Microsoft Exchange and related products to mitigate potential vulnerabilities.

Patching and Updates

Stay informed about security updates and patches released by Microsoft for Exchange and associated products to address vulnerabilities promptly.