CVE-2017-2818 in Poppler
Summary
by MITRE
An exploitable heap overflow vulnerability exists in the image rendering functionality of Poppler 0.53.0. A specifically crafted PDF can cause an overly large number of color components during image rendering, resulting in heap corruption. An attacker controlled PDF file can be used to trigger this vulnerability.
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Analysis
by VulDB Data Team • 12/12/2022
The vulnerability identified as CVE-2017-2818 represents a critical heap overflow condition within the Poppler PDF rendering library version 0.53.0, which falls under the broader category of memory safety issues classified as CWE-121. This vulnerability specifically impacts the image rendering functionality of the library, making it a significant concern for applications that process untrusted PDF content. The flaw arises from inadequate input validation during the parsing of color component specifications within PDF image data, creating a scenario where maliciously crafted PDF files can trigger buffer overflow conditions in the heap memory space.
The technical implementation of this vulnerability stems from the way Poppler handles color component data during image rendering operations. When processing PDF files containing specially crafted image data, the library fails to properly validate the number of color components specified in the image data structure. This validation failure allows an attacker to specify an excessive number of color components that exceeds the allocated heap buffer size. The heap overflow occurs because the memory allocation routine does not account for the potential size of the color component array, leading to memory corruption that can overwrite adjacent heap allocations and potentially corrupt the heap metadata structures.
Operationally, this vulnerability presents a severe threat to systems that rely on Poppler for PDF processing, including web browsers, document viewers, and content management systems. The exploitation of this heap overflow can result in arbitrary code execution, making it particularly dangerous for server-side applications and automated PDF processing systems. Attackers can craft PDF files that, when opened by vulnerable applications, trigger the overflow condition and potentially allow remote code execution. The vulnerability's impact extends beyond simple denial of service scenarios, as the heap corruption can be leveraged to achieve privilege escalation or system compromise depending on the execution context of the affected application.
The attack vector for this vulnerability is straightforward and requires minimal technical expertise to exploit effectively. An attacker only needs to create a malicious PDF file containing malformed color component data that will trigger the heap overflow when processed by any application using the vulnerable Poppler library. This makes the vulnerability particularly dangerous in environments where users frequently open PDF documents from untrusted sources, such as email attachments, web downloads, or file sharing platforms. The vulnerability's exploitation can be automated and does not require user interaction beyond opening the malicious document, making it a preferred target for phishing campaigns and other social engineering attacks.
Mitigation strategies for CVE-2017-2818 should prioritize immediate patching of affected Poppler installations to version 0.54.0 or later, which contains the necessary fixes for the heap overflow condition. Organizations should also implement defensive measures such as sandboxing PDF processing applications, implementing strict input validation for PDF files, and deploying web application firewalls that can detect and block malicious PDF content. Additionally, security teams should consider implementing network-based detection rules that monitor for PDF file transfers containing suspicious color component specifications, aligning with ATT&CK technique T1059.007 for execution through PDF files. System administrators should also conduct thorough vulnerability assessments to identify all systems using vulnerable Poppler versions and ensure comprehensive patch management procedures are in place to prevent similar vulnerabilities from being exploited in the future.