Microsoft has released four security patches that all Outlook for Windows need to protect from newly discovered bugs. The patches apply to Outlook 365, 2019, 2016, 2013 and 2010 for Windows and are available today.
The four Outlook security bugs are related. They involved a hacked .RWZ file that could be sent to you via email or messaging. Fortinet discovered the Outlook bugs and quietly told Microsoft.
An .RWZ file is an Outlook Rules export file. It’s a way to copy, share or backup Outlook Rules.
What you need to do
Update your Microsoft Office in the usual way. For modern Office go to File | Account | Update Options | Update Now.
Office will download and install any available patches.
Naturally, be wary of strange attachments in emails.
Microsoft hides the bad news
Someone could base a thesis on Microsoft’s masterful obfuscation of bad news. They’ve managed to make the constant run of security bugs in their products seem bland and insignificant.
The month’s RWZ related security bugs are just the latest lapses in Microsoft Office. But reading their self-serving documentation make it seem like ‘no big deal’.
Check out Microsoft’s version of the Outlook security bug coded CVE-2018-8522. Microsoft’s text makes NO mention of .RWZ files at all! No warning that .RWZ files are a security risk.
That’s because the text is standard boilerplate text that’s used over and over again with little, if any, variation.
CVE-2018-8582 is the fourth of the bugs. The text is slightly different because this is an RWZ parsing bug not a memory bug. At least there’s a reference to .RWZ files, buried deep in the paragraph.
CVE-2018-8522 | Microsoft Outlook Remote Code Execution Vulnerability
CVE-2018-8524 | Microsoft Outlook Remote Code Execution Vulnerability
CVE-2018-8576 | Microsoft Outlook Remote Code Execution Vulnerability
All use this main ‘explanatory’ text:
“A remote code execution vulnerability exists in Microsoft Outlook software when it fails to properly handle objects in memory. An attacker who successfully exploited the vulnerability could use a specially crafted file to perform actions in the security context of the current user. For example, the file could then take actions on behalf of the logged-on user with the same permissions as the current user.
To exploit the vulnerability, a user must open a specially crafted file with an affected version of Microsoft Outlook software. In an email attack scenario, an attacker could exploit the vulnerability by sending the specially crafted file to the user and convincing the user to open the file. In a web-based attack scenario, an attacker could host a website (or leverage a compromised website that accepts or hosts user-provided content) that contains a specially crafted file that is designed to exploit the vulnerability. However, an attacker would have no way to force the user to visit the website. Instead, an attacker would have to convince the user to click a link, typically by way of an enticement in an email or Instant Messenger message, and then convince the user to open the specially crafted file.
Note that the Preview Pane is not an attack vector for this vulnerability.
The security update addresses the vulnerability by correcting how Microsoft Outlook handles files in memory.”
CVE-2018-8582 | Microsoft Outlook Remote Code Execution Vulnerability
“A remote code execution vulnerability exists in the way that Microsoft Outlook parses specially modified rule export files.
An attacker who successfully exploited this vulnerability could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights. Systems such as workstations and terminal servers where Microsoft Outlook is used are at risk. Servers could be at more risk if administrators allow users to log on to servers and to run programs. However, best practices strongly discourage allowing this.
In an email attack scenario, an attacker could exploit the vulnerability by sending a specially crafted email message to the user and then convincing the user to open the email and import an attached .rwz (rule export) file. Exploitation of this vulnerability requires that a user open a specially crafted email message with an affected version of Microsoft Outlook, download a malicious attachment, and manually import the contents of the attachment using the Outlook user interface.
The update addresses the vulnerability by correcting the way that Microsoft Outlook parses rule export files.”