CVE-2018-0819 in Office
Summary
by MITRE
Microsoft Office 2016 for Mac allows an attacker to send a specially crafted email attachment to a user in an attempt to launch a social engineering attack, such as phishing, due to how Outlook for Mac displays encoded email addresses, aka "Spoofing Vulnerability in Microsoft Office for Mac."
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 08/18/2024
The vulnerability identified as CVE-2018-0819 represents a significant security flaw in Microsoft Office 2016 for Mac that enables sophisticated social engineering attacks through email spoofing. This vulnerability specifically affects how Outlook for Mac handles and displays encoded email addresses, creating opportunities for attackers to manipulate the appearance of sender information in email messages. The flaw operates at the user interface level where the application fails to properly validate or sanitize encoded email address formats, allowing malicious actors to craft deceptive email headers that appear legitimate to unsuspecting users. This vulnerability is particularly dangerous because it targets the fundamental trust users place in email sender information, which forms the basis of many phishing and spear-phishing campaigns.
The technical implementation of this vulnerability stems from inadequate input validation within the email address parsing and rendering mechanisms of Outlook for Mac. When processing encoded email addresses that contain special characters, HTML entities, or other encoded formats, the application does not properly sanitize or verify the authenticity of the displayed information. This allows attackers to exploit the encoding mechanisms to create misleading sender addresses that may appear to originate from trusted sources. The vulnerability is classified under CWE-20, which deals with improper input validation, and specifically relates to CWE-601, URL Redirection to Untrusted Site, as the spoofed addresses can lead users to malicious destinations. The flaw exists in the email rendering engine that processes and displays email headers, particularly when dealing with internationalized domain names or complex encoding schemes.
The operational impact of CVE-2018-0819 extends beyond simple email spoofing to enable comprehensive social engineering campaigns that can bypass traditional email security measures. Attackers can leverage this vulnerability to create convincing phishing emails that appear to come from legitimate sources such as financial institutions, government agencies, or corporate executives. The vulnerability is particularly effective in corporate environments where users may not be trained to recognize subtle differences in email address formatting or encoding. This flaw can be exploited in targeted attacks where attackers craft emails that look authentic to the recipient, potentially leading to successful credential theft, financial fraud, or data breaches. The vulnerability is categorized under the ATT&CK technique T1566, "Phishing", and specifically relates to T1566.001, "Phishing: Spearphishing Attachment", as it enables attackers to deliver malicious payloads through deceptive email attachments.
Organizations can mitigate this vulnerability through multiple defensive strategies that address both technical and user awareness components. Microsoft released patches and updates to address the encoding validation issues in affected Outlook for Mac versions, requiring users to maintain current software versions. System administrators should implement email filtering solutions that can detect and quarantine suspicious email patterns, particularly those containing unusual encoding or address formatting. User education programs should focus on teaching employees to verify sender addresses, pay attention to subtle differences in email formatting, and verify the legitimacy of unexpected attachments through independent verification methods. Network security teams should monitor email traffic for patterns consistent with spoofing attempts and implement additional layers of authentication such as DMARC, SPF, and DKIM validation to provide additional protection against these types of attacks. The vulnerability demonstrates the importance of proper input validation and the need for comprehensive security testing of user interface components that handle external data processing.