CVE-2015-1263 in Chrome
Summary
by MITRE
The Spellcheck API implementation in Google Chrome before 43.0.2357.65 does not use an HTTPS session for downloading a Hunspell dictionary, which allows man-in-the-middle attackers to deliver incorrect spelling suggestions or possibly have unspecified other impact via a crafted file.
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Analysis
by VulDB Data Team • 05/19/2022
The vulnerability identified as CVE-2015-1263 resides within the Spellcheck API implementation of Google Chrome versions prior to 43.0.2357.65, representing a critical security flaw that undermines the integrity of spell checking functionality. This weakness specifically manifests when the browser attempts to download Hunspell dictionary files, which are essential components for providing spell checking services to users. The vulnerability stems from the application's failure to enforce secure communication protocols during the dictionary download process, creating an exploitable condition that adversaries can leverage for malicious purposes.
The technical flaw in question constitutes a failure to implement proper transport layer security measures, specifically the absence of HTTPS encryption during the download of Hunspell dictionaries. This insecure implementation allows attackers positioned in man-in-the-middle positions to intercept and manipulate the communication between the browser and the dictionary servers. The vulnerability operates at the application layer of the network stack, where the Spellcheck API component handles external resource retrieval without adequate security validation. According to CWE-319, this represents a weakness in which sensitive information is transmitted using an insecure channel, making it susceptible to interception and modification by unauthorized parties. The flaw directly violates the principle of secure communication and demonstrates poor security implementation practices within the browser's spell checking infrastructure.
The operational impact of this vulnerability extends beyond simple spell checking manipulation, potentially enabling sophisticated attack scenarios that could compromise user data and system integrity. Attackers can deliver incorrect spelling suggestions that may mislead users into accepting maliciously modified dictionary content, which could contain phishing indicators or other deceptive elements. The unspecified other impacts mentioned in the vulnerability description suggest that this weakness might enable additional attack vectors beyond simple content manipulation. This vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter, as the modified dictionary content could potentially contain malicious payloads or commands that execute within the browser environment. The security implications are particularly severe for users who rely heavily on spell checking features, as the vulnerability could be exploited to deliver deceptive content that appears legitimate within the browser interface.
Mitigation strategies for CVE-2015-1263 require immediate remediation through browser updates to versions 43.0.2357.65 and later, which properly implement HTTPS encryption for dictionary downloads. Organizations should prioritize patch management to ensure all affected Chrome installations are updated promptly, as the vulnerability remains exploitable in older versions. Network administrators should consider implementing additional monitoring for suspicious dictionary download activities and traffic patterns that might indicate exploitation attempts. The vulnerability highlights the importance of secure coding practices and the necessity of implementing proper transport layer security for all external resource downloads. Security teams should conduct vulnerability assessments to identify other applications or systems that might exhibit similar insecure communication patterns, particularly those that download external dictionaries or language resources. Organizations may also consider implementing network-level protections such as SSL inspection capabilities to detect and prevent man-in-the-middle attacks targeting spell checking functionality. This vulnerability underscores the critical need for security controls that enforce secure communication channels for all external resource interactions, as specified in security frameworks like NIST SP 800-53 and ISO 27001 controls related to secure communication and data integrity.