KLA11102 Multiple vulnerabilities in Microsoft Exchange Server

Multiple serious vulnerabilities have been found in Microsoft Exchange Server. Malicious users can exploit these vulnerabilities to obtain sensitive information and gain privileges.

Below is a complete list of vulnerabilities:

1. An incorrect parsing of Calendar-related messages can be exploited by sending Calendar-related messages with specially designed tags to server to obtain sensitive information.
2. An improper validation of webrequests in Microsoft Exchange (OWA) Outlook Web Access can be exploited remotely by convincing a user to click a specially designed link to gain privileges.

NB: Not every vulnerability already has CVSS rating, so cumulative CVSS rating can be not representative.

NB: These vulnerabilities do not have any public CVSS rating, so rating can be changed by the time.

Original advisories

CVE-2017-8758

CVE-2017-11761

Related products

Microsoft-Exchange-Server

CVE list

CVE-2017-11761 warning

CVE-2017-8758 warning

KB list

4036108

4045655

Solution

Install necessary updates from the KB section, that are listed in your Windows Update (Windows Update usually can be accessed from the Control Panel)

Impacts

• OSI

Obtain sensitive information. Exploitation of vulnerabilities with this impact can lead to capturing by abuser information, critical for user or system.

• SB

Security bypass. Exploitation of vulnerabilities with this impact can lead to performing actions restricted by current security settings.

• PE

Privilege escalation. Exploitation of vulnerabilities with this impact can lead to performing by abuser actions, which are normally disallowed for current role.

Affected Products

• Microsoft Exchange Server 2013 Cumulative Update 16Microsoft Exchange Server 2013 Cumulative Update 17Microsoft Exchange Server 2013 Service Pack 1Microsoft Exchange Server 2016 Cumulative Update 5Microsoft Exchange Server 2016 Cumulative Update 6