CVE-2005-3353 in PHP
Summary
by MITRE
The exif_read_data function in the Exif module in PHP before 4.4.1 allows remote attackers to cause a denial of service (infinite loop) via a malformed JPEG image.
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Analysis
by VulDB Data Team • 07/06/2021
The vulnerability identified as CVE-2005-3353 represents a critical denial of service weakness within the PHP Exif module that affected versions prior to 4.4.1. This flaw specifically targets the exif_read_data function which is responsible for parsing and extracting metadata from jpeg image files. The vulnerability arises from inadequate input validation and error handling within the Exif parsing logic, creating a condition where malformed jpeg data can trigger an infinite loop during processing. Attackers can exploit this by crafting specially designed jpeg images that contain malformed exif data, causing the php process to enter an endless loop consuming system resources and effectively rendering the service unavailable to legitimate users.
The technical implementation of this vulnerability stems from the Exif module's failure to properly validate jpeg image structures before attempting to parse exif metadata. When the exif_read_data function encounters malformed data, it does not implement proper bounds checking or loop termination conditions, allowing the parsing routine to continue indefinitely. This behavior aligns with CWE-835 which specifically addresses infinite loops or iterations that can lead to denial of service conditions. The vulnerability demonstrates poor defensive programming practices where the code assumes valid input without adequate validation mechanisms to prevent malicious data from causing system instability.
From an operational perspective, this vulnerability creates significant security implications for web applications that process user-uploaded jpeg images. The infinite loop condition can be triggered through simple http requests containing maliciously crafted jpeg files, making it particularly dangerous for applications that accept file uploads or process external image sources. The resource exhaustion effect can lead to complete service unavailability, impacting not only the targeted application but potentially affecting the entire server if multiple processes are simultaneously consumed. This vulnerability directly maps to ATT&CK technique T1499.004 which involves resource exhaustion attacks, and demonstrates how seemingly benign image processing functionality can become a vector for system disruption.
The mitigation strategy for this vulnerability requires immediate upgrading of affected PHP installations to version 4.4.1 or later where the Exif module has been patched to properly handle malformed jpeg data. System administrators should also implement additional input validation layers at the application level to detect and reject suspicious image files before they reach the exif parsing functions. Network-level firewalls can be configured to filter out known malicious image patterns, while application firewalls can monitor for unusual processing patterns that might indicate exploitation attempts. Additionally, implementing proper resource limits and timeouts for image processing operations can help contain the impact if exploitation occurs despite preventive measures. Organizations should also consider implementing automated monitoring systems to detect unusual resource consumption patterns that might indicate successful exploitation of this vulnerability.