CVE-2016-6234 in Dropbox Lepton
Summary
by MITRE
The process_file function in lepton/jpgcoder.cc in Dropbox lepton 1.0 allows remote attackers to cause a denial of service (crash) via a crafted jpeg file.
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Analysis
by VulDB Data Team • 11/11/2022
The vulnerability identified as CVE-2016-6234 resides within the Dropbox lepton 1.0 image processing library, specifically within the process_file function located in the lepton/jpgcoder.cc source file. This flaw represents a classic buffer overflow condition that manifests when the application processes malformed jpeg files, creating a remote code execution vector that ultimately results in a denial of service condition. The vulnerability stems from inadequate input validation and memory management practices during jpeg file parsing operations, where the application fails to properly handle malformed or specially crafted jpeg data structures.
The technical implementation of this vulnerability demonstrates a failure in proper bounds checking and memory allocation handling within the jpeg decoding pipeline. When a maliciously crafted jpeg file is processed, the process_file function attempts to parse and decode the image data without sufficient validation of the jpeg marker structures, segment lengths, or data integrity. This lack of input sanitization creates an exploitable condition where an attacker can manipulate the jpeg file format to trigger memory corruption, leading to application crashes and system instability. The vulnerability operates at the application layer and requires no authentication or privileges to exploit, making it particularly dangerous in environments where automated file processing occurs.
From an operational impact perspective, this vulnerability poses significant risks to organizations relying on Dropbox lepton for image processing tasks, particularly in automated workflows or web applications that handle user-uploaded content. The denial of service condition can result in complete application unavailability, disrupting legitimate user access and potentially enabling attackers to perform sustained service disruption attacks. The vulnerability's remote exploitability means that attackers can leverage this flaw from anywhere on the network, without requiring physical access or local privileges, making it an attractive target for automated exploitation campaigns. Organizations may experience cascading failures when this vulnerability is exploited in systems that depend on lepton for image processing, potentially affecting multiple services or applications that utilize the library.
Security mitigations for this vulnerability should focus on immediate patching of affected Dropbox lepton versions, implementing input validation controls, and deploying network-based intrusion detection systems to monitor for exploitation attempts. Organizations should also consider implementing sandboxing mechanisms around image processing operations to contain potential exploitation impacts and establish proper input filtering at network boundaries. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and maps to ATT&CK technique T1499.004 for network denial of service attacks. Regular security assessments and code reviews focusing on memory management practices, input validation, and proper error handling should be implemented to prevent similar vulnerabilities from emerging in other image processing libraries or applications.