CVE-2017-8663 in Outlook
Summary
by MITRE
Microsoft Outlook 2007 SP3, Outlook 2010 SP2, Outlook 2013 SP1, Outlook 2013 RT SP1, and Outlook 2016 as packaged in Microsoft Office allows a remote code execution vulnerability due to the way Microsoft Outlook parses specially crafted email messages, aka "Microsoft Office Outlook Memory Corruption Vulnerability"
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Analysis
by VulDB Data Team • 01/06/2021
The vulnerability identified as CVE-2017-8663 represents a critical memory corruption issue within Microsoft Outlook client applications that affects multiple versions including Outlook 2007 SP3, Outlook 2010 SP2, Outlook 2013 SP1, Outlook 2013 RT SP1, and Outlook 2016. This flaw operates at the core parsing mechanisms of the email client, specifically when processing malformed or specially crafted email messages that contain maliciously constructed data structures. The vulnerability stems from insufficient input validation and memory management practices within the Outlook application's email parsing engine, creating an environment where malicious actors can exploit memory corruption to execute arbitrary code on affected systems.
The technical nature of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions where an application accesses memory outside the bounds of a buffer, and CWE-787, which covers out-of-bounds write operations that can overwrite adjacent memory locations. These memory corruption vulnerabilities typically occur when the application fails to properly validate the size and structure of incoming data before processing it, allowing attackers to manipulate memory layout and potentially overwrite critical program structures or execute malicious payloads. The vulnerability manifests when Outlook attempts to parse email attachments or message content that contains crafted malicious data sequences designed to trigger buffer overflow conditions or memory corruption states.
From an operational perspective, this vulnerability poses significant risks to enterprise environments as it enables remote code execution without requiring user interaction beyond receiving a malicious email message. The attack vector is particularly dangerous because it leverages the trust relationship that exists between users and their email clients, making it difficult to distinguish between legitimate and malicious email content. Attackers can craft emails that appear normal but contain hidden malicious code that exploits the memory corruption flaw during the parsing process, potentially leading to full system compromise, data exfiltration, or lateral movement within network environments. This vulnerability directly maps to ATT&CK technique T1204.002, which involves user execution of malicious content through email attachments or links.
The impact of this vulnerability extends beyond individual user systems to affect entire organizational email infrastructures, as a single compromised Outlook client can potentially serve as a foothold for broader network infiltration. Organizations that rely heavily on Outlook for email communication face elevated risk levels, particularly those without robust email filtering mechanisms or endpoint protection solutions that can detect and prevent exploitation attempts. The vulnerability's exploitation requires minimal user interaction beyond opening or previewing the malicious email, making it particularly effective for social engineering campaigns. Microsoft's security response included emergency patches and updates to address the memory corruption issues, but the vulnerability's presence in multiple Outlook versions created extended exposure windows for organizations that had not yet applied the necessary security updates. Organizations implementing layered security approaches including email filtering, network segmentation, and regular security updates can significantly reduce the risk of successful exploitation attempts.