CVE-2017-11776 in Outlook
Summary
by MITRE
Microsoft Outlook 2016 allows an attacker to obtain the email content of a user, due to how Outlook 2016 discloses user email content, aka "Microsoft Outlook Information Disclosure Vulnerability."
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Analysis
by VulDB Data Team • 01/16/2021
The CVE-2017-11776 vulnerability represents a critical information disclosure flaw in Microsoft Outlook 2016 that enables attackers to access email content without proper authorization. This vulnerability stems from improper handling of email messages within the Outlook application, specifically affecting how the software processes and displays email content to users. The flaw manifests when Outlook 2016 encounters certain email formats or attachments that trigger unexpected behavior in the application's rendering engine, potentially exposing sensitive user data. This vulnerability falls under the broader category of information disclosure weaknesses that can lead to unauthorized access to confidential communications and personal data.
The technical implementation of this vulnerability involves Outlook's processing of specific email message structures that cause the application to inadvertently reveal email content through improper memory handling or display mechanisms. When an attacker crafts a malicious email with specific formatting or encoding patterns, the Outlook client may process these elements in a way that exposes internal data structures or allows for unauthorized content retrieval. This behavior typically occurs during the parsing or rendering phase of email processing, where the application fails to properly validate or sanitize incoming message data before displaying it to the user. The vulnerability is particularly concerning because it operates at the application level rather than the network level, making it more difficult to detect through traditional network monitoring approaches.
The operational impact of CVE-2017-11776 extends beyond simple information disclosure, as it can enable attackers to access sensitive business communications, personal correspondence, and potentially confidential organizational data. This vulnerability affects organizations where Outlook 2016 is the primary email client, potentially compromising user privacy and corporate security. The risk is heightened when users receive emails from untrusted sources or when the application processes emails with embedded malicious content. Attackers can leverage this vulnerability to gather intelligence, conduct social engineering campaigns, or extract sensitive information from targeted individuals within an organization. The vulnerability's impact is particularly severe in environments where Outlook 2016 is used for handling sensitive communications, including financial, legal, or healthcare-related correspondence.
Mitigation strategies for CVE-2017-11776 should focus on both immediate patching and defensive measures. Microsoft released security updates to address this vulnerability, and organizations should prioritize applying these patches to all affected Outlook 2016 installations. Additionally, implementing email filtering solutions that can detect and quarantine suspicious email patterns can provide additional protection layers. Network administrators should consider implementing strict email content filtering policies and educating users about the risks of opening suspicious emails. The vulnerability aligns with CWE-200, which addresses information exposure, and can be mapped to ATT&CK technique T1059 for command and scripting interpreter usage in exploitation scenarios. Organizations should also consider implementing email encryption solutions and maintaining robust backup systems to ensure data integrity and availability in case of successful exploitation attempts.