CVE-2017-11110 in Catdoc
Summary
by MITRE
The ole_init function in ole.c in catdoc 0.95 allows remote attackers to cause a denial of service (heap-based buffer underflow and application crash) or possibly have unspecified other impact via a crafted file, i.e., data is written to memory addresses before the beginning of the tmpBuf buffer.
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Analysis
by VulDB Data Team • 10/24/2019
The vulnerability identified as CVE-2017-11110 resides within the ole_init function of the catdoc 0.95 document processing library, specifically in the ole.c source file. This flaw represents a heap-based buffer underflow condition that occurs when processing specially crafted Office document files. The vulnerability manifests when the application attempts to write data to memory locations that precede the allocated tmpBuf buffer, creating a dangerous condition where memory corruption can occur. Such buffer underflow vulnerabilities are particularly concerning as they can lead to unpredictable application behavior and potential exploitation by malicious actors.
The technical implementation of this vulnerability stems from inadequate bounds checking within the ole_init function. When catdoc processes a malformed Office file, the function fails to properly validate the size and structure of incoming data before attempting to write to the tmpBuf buffer. This oversight allows attackers to craft malicious documents that contain data sequences designed to overflow the buffer's boundaries, specifically targeting memory locations that precede the buffer's allocated space. The flaw operates at the memory management level, where the application's handling of buffer boundaries becomes compromised, potentially allowing for memory corruption that can be leveraged for more serious exploits.
From an operational impact perspective, this vulnerability creates significant risks for organizations relying on catdoc for document processing and analysis. The denial of service condition can cause applications to crash or become unresponsive when processing malicious documents, effectively disrupting business operations and potentially creating availability issues for document handling systems. The unspecified other impacts mentioned in the vulnerability description suggest that beyond simple application crashes, this buffer underflow could potentially enable more sophisticated attacks such as arbitrary code execution or privilege escalation. The vulnerability affects systems that utilize catdoc for processing Microsoft Office documents, making it particularly relevant for environments that handle document analysis, email filtering, or automated document processing workflows.
Security mitigations for CVE-2017-11110 should prioritize immediate patching of the catdoc library to version 0.96 or later, which contains the necessary fixes for the buffer underflow condition. Organizations should also implement defensive measures such as input validation for all Office document processing, particularly for files received from untrusted sources. Network segmentation and content filtering solutions should be configured to scan and block potentially malicious Office documents before they reach systems that utilize catdoc. The vulnerability aligns with CWE-121, heap-based buffer overflow, and could potentially map to ATT&CK techniques involving privilege escalation or denial of service through memory corruption. System administrators should also consider implementing monitoring for application crashes or unexpected behavior when processing Office documents, as these could indicate exploitation attempts. Additionally, regular security assessments of document processing pipelines should be conducted to identify other potential vulnerabilities that could be exploited in similar ways.