What is CVE-2017-0199 vulnerability?
CVE-2017-0199 is a Remote Code Execution (RCE) vulnerability in Microsoft Office and WordPad. It arises through the improper handling of Object Linking and Embedding (OLE) objects, enabling attackers to execute arbitrary code by sending a maliciously crafted document or RTF (Rich Text Format) file. Exploiting this vulnerability can grant attackers the ability to compromise systems, steal sensitive data, or perform lateral movement across networks.
When was it discovered?
CVE-2017-0199 was first disclosed on April 11, 2017, with a formal security update released by Microsoft on the same day. Security researchers discovered the vulnerability after observing targeted attacks employing malicious documents.
Affected products & versions
Product | Versions Affected | Fixed Versions / Patch Links |
Microsoft Office | 2007, 2010, 2013, 2016 | April 2017 Security Patch (Microsoft Update Guide) |
WordPad | Windows 7, 8, 10 | April 2017 Security Updates (Microsoft Update Guide) |
CVE-2017-0199 technical description
CVE-2017-0199 exploits how Microsoft Office applications handle HTA (HTML Application) files embedded within OLE objects. Attackers craft a seemingly legitimate document that, upon opening, retrieves an external HTA file containing malicious scripts. This file is then executed without the user's consent, allowing the attacker to gain control over the system. The vulnerability stems from the lack of adequate validation of external content paths and insufficient sandboxing of embedded objects.
Tactics, Techniques & Procedures (TTPs)
Attackers typically employ spear-phishing campaigns, attaching malicious Office documents or RTF files to emails. Upon opening the payload, the file downloads external malicious scripts, often leading to the deployment of malware such as remote access trojans.
Indicators of compromise
Indicators include unauthorized HTTP/HTTPS requests to suspicious external domains, execution of HTA scripts, and unusual document behaviors like prompting for external links. Monitor for file extensions such as .hta or malicious traffic originating from Office applications.
Known proof-of-concepts & exploits
Public proof-of-concept exploit code is available on platforms like GitHub. There have been widespread reports of active exploitation campaigns targeting enterprises and individuals, particularly in 2017, leveraging this vulnerability for espionage and financial fraud.
How to detect CVE-2017-0199 vulnerability?
This vulnerability can be detected by analyzing SIEM logs for abnormal HTTP requests and file downloads triggered by Office processes. Host-based monitoring can identify HTA file execution and unusual child processes stemming from offline Office or WordPad applications. Utilize updated antivirus software or endpoint detection solutions to flag malicious macro behavior.
Impact & risk of CVE-2017-0199 vulnerability
The CVE-2017-0199 exploit compromises data confidentiality, integrity, and availability. It has been used in delivering malware for espionage, ransomware, and credential theft operations. An unpatched system can enable attackers to spread laterally across networks, compromising enterprise infrastructure.
Mitigation & remediation strategies
Prevent exploitation by applying Microsoft’s April 2017 security patch across affected systems. Disable embedded object execution within Office applications where possible. Additionally, organizations should implement advanced email filtering and educate employees on identifying phishing emails. Employing endpoint detection and response (EDR) tools helps monitor and block suspicious behavior effectively.
CVE-2017-0199 Vulnerability FAQs
CVE-2017-0199 is a Remote Code Execution (RCE) vulnerability in Microsoft Office and WordPad, allowing attackers to exploit OLE objects to execute malicious scripts. Exploitation occurs when a user opens a specially crafted document or RTF file.
Systems are infected when users open a malicious document delivered through phishing emails. These documents download external HTA files containing code that attackers can use to take control of the system.
While the initial exploits declined after 2017, unpatched systems remain at risk. Attackers may leverage the vulnerability in legacy environments without updated security patches. Regular updates and proactive monitoring are critical safeguards.
Apply Microsoft’s security patch released in April 2017. Use advanced threat detection tools, disable object execution in Office files, and train employees on phishing awareness. Monitor system logs for suspicious behaviors related to HTA scripts or malicious file downloads.
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