CVE-2011-1979 in Visio
Summary
by MITRE
Microsoft Visio 2003 SP3 and 2007 SP2 does not properly validate objects in memory during Visio file parsing, which allows remote attackers to execute arbitrary code via a crafted file, aka "Move Around the Block RCE Vulnerability."
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Analysis
by VulDB Data Team • 11/17/2021
The vulnerability identified as CVE-2011-1979 represents a critical remote code execution flaw affecting Microsoft Visio 2003 Service Pack 3 and Visio 2007 Service Pack 2. This vulnerability stems from insufficient input validation mechanisms within the Visio file parsing engine, specifically during the processing of Visio file objects in memory. The flaw enables attackers to craft malicious Visio files that, when opened by an affected system, trigger arbitrary code execution on the target machine. The vulnerability is particularly concerning because it operates through legitimate file parsing operations, making it difficult to distinguish between benign and malicious documents at runtime.
The technical root cause of this vulnerability lies in the improper validation of objects within Visio's memory management system during file parsing operations. When Visio processes a Visio file, it loads various objects into memory without adequate bounds checking or validation of object integrity. This memory handling flaw creates an opportunity for attackers to manipulate the file structure in such a way that when the parsing engine encounters specially crafted objects, it executes code from unexpected memory locations. The vulnerability specifically affects how Visio handles certain object types during the parsing sequence, allowing attackers to overwrite memory locations or redirect execution flow through buffer overflow conditions or similar memory corruption techniques.
The operational impact of CVE-2011-1979 extends significantly beyond simple code execution, as it provides attackers with a vector for complete system compromise. Since Visio is commonly used in business environments for diagramming and technical documentation, the attack surface is broad and includes corporate networks where these applications are frequently installed. The remote nature of the vulnerability means that attackers can deliver malicious Visio files through email attachments, web downloads, or file sharing systems without requiring local access to the target system. This characteristic aligns with ATT&CK technique T1204.002 for exploitation through malicious file execution, making it particularly dangerous in enterprise environments where users may inadvertently open malicious documents.
The vulnerability's classification as a memory corruption issue places it within CWE-125, which describes out-of-bounds read conditions that can lead to arbitrary code execution. This categorization reflects the fundamental problem of insufficient bounds checking during memory operations, where the parsing engine fails to properly validate object sizes and memory boundaries. Organizations running affected Visio versions face significant risk as attackers can leverage this vulnerability to establish persistent access, escalate privileges, or deploy additional malware payloads. The attack requires no specialized knowledge beyond basic file crafting skills, making it accessible to threat actors of varying skill levels.
Mitigation strategies for CVE-2011-1979 should focus on immediate patching of affected Visio installations to address the memory validation deficiencies. Microsoft released security updates that corrected the object validation logic within the Visio parsing engine, preventing the exploitation of this vulnerability. Organizations should also implement strict file validation policies that limit Visio file processing to trusted sources and consider deploying email filtering solutions that block potentially malicious Visio attachments. Network segmentation and application whitelisting can further reduce the attack surface by limiting where Visio applications can be executed and what files they can process. Additionally, user education programs should emphasize the importance of avoiding untrusted Visio files and recognizing potential social engineering attempts that might deliver malicious documents through common attack vectors such as phishing campaigns.