CVE-2017-0194 in Excel
Summary
by MITRE
Microsoft Excel 2007 SP3, Microsoft Excel 2010 SP2, and Office Compatibility Pack SP2 allow remote attackers to obtain sensitive information from process memory via a crafted Office document, aka "Microsoft Office Information Disclosure Vulnerability."
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 11/28/2022
The vulnerability identified as CVE-2017-0194 represents a critical information disclosure flaw affecting multiple versions of Microsoft Excel and the Office Compatibility Pack. This vulnerability stems from improper handling of specially crafted Office documents that can trigger memory corruption conditions within the affected applications. The flaw specifically impacts Microsoft Excel 2007 SP3, Excel 2010 SP2, and the Office Compatibility Pack SP2, creating a significant security risk for organizations relying on these legacy applications. The vulnerability operates through a remote attack vector, meaning malicious actors can exploit it without requiring physical access to target systems, making it particularly dangerous in enterprise environments where users frequently open documents from untrusted sources.
The technical mechanism behind this information disclosure vulnerability involves the manipulation of Office document parsing routines during the processing of maliciously crafted files. When an affected Excel application encounters such a document, the parsing logic fails to properly validate input data structures, leading to memory access violations that can expose sensitive information from the application's process memory. This memory disclosure can potentially reveal cryptographic keys, authentication tokens, or other confidential data that resides in the application's memory space. The vulnerability is classified under CWE-200, which specifically addresses "Information Exposure," and aligns with ATT&CK technique T1059.005 for "Command and Scripting Interpreter: Visual Basic" as attackers may leverage this information to construct more sophisticated attacks. The flaw demonstrates how improper input validation in document processing applications can create pathways for attackers to extract valuable data from memory segments that should remain protected.
The operational impact of CVE-2017-0194 extends beyond simple information disclosure, as the leaked memory contents can provide attackers with sufficient information to conduct more advanced exploitation techniques. Organizations using affected versions of Excel face potential risks including credential theft, session hijacking, and privilege escalation attacks that could compromise entire network infrastructures. The vulnerability's remote nature means that attackers can deploy malicious documents through email campaigns, web downloads, or compromised websites, making it extremely difficult to defend against without proper patch management. Security professionals must consider that this vulnerability could be exploited as part of larger attack campaigns where the initial information disclosure serves as a reconnaissance step before deploying more destructive payloads. The risk assessment for this vulnerability is particularly high given that many organizations continue to use legacy Office applications due to compatibility requirements, creating extended attack surfaces that persist long after the vulnerability was first discovered.
Mitigation strategies for CVE-2017-0194 must address both immediate protection needs and long-term security posture improvements. Organizations should prioritize applying the official Microsoft security updates that resolve this vulnerability, as these patches specifically target the memory handling flaws in the affected Excel versions. Additionally, implementing strict document validation policies, including disabling macro execution in Office applications, can significantly reduce exploitation risk. Network-based protections such as email filtering systems should be configured to block suspicious Office document attachments, while endpoint protection solutions should be updated to detect and prevent execution of malicious Office files. The vulnerability highlights the importance of maintaining up-to-date security patches across all Microsoft Office installations and demonstrates why organizations should establish comprehensive vulnerability management programs. Security teams should also consider implementing memory protection mechanisms such as Data Execution Prevention (DEP) and Address Space Layout Randomization (ASLR) to make exploitation attempts more difficult even if attackers manage to bypass initial defenses. Regular security awareness training for users about the dangers of opening untrusted Office documents remains crucial in defending against social engineering aspects of this vulnerability.