CVE-2013-1013 in Safari
Summary
by MITRE
XSS Auditor in WebKit in Apple Safari before 6.0.5 does not properly rewrite URLs, which allows remote attackers to trigger unintended form submissions via unspecified vectors.
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Analysis
by VulDB Data Team • 05/14/2021
The vulnerability identified as CVE-2013-1013 represents a significant cross-site scripting weakness within Apple Safari's WebKit rendering engine that persisted through versions prior to 6.0.5. This flaw specifically affects the XSS Auditor component, which is designed to protect web browsers from malicious cross-site scripting attacks by automatically detecting and preventing potentially dangerous script execution. The vulnerability arises from the improper URL rewriting mechanism within the XSS Auditor, creating a pathway for remote attackers to exploit form submission behaviors in ways that were not anticipated by the security system. The flaw operates at the browser level rather than the web application level, making it particularly dangerous as it can bypass traditional web application security controls that developers might have implemented.
The technical implementation of this vulnerability stems from the XSS Auditor's failure to correctly sanitize or rewrite URLs when processing web content, particularly in scenarios involving form submissions. When a malicious actor crafts a specially designed web page that includes crafted form elements or JavaScript code, the improperly functioning URL rewriting mechanism allows these elements to be interpreted differently than intended. This creates a situation where legitimate form submissions can be triggered by malicious code without proper user consent or awareness, potentially leading to unauthorized actions being performed on behalf of the user. The unspecified vectors mentioned in the vulnerability description suggest that the attack surface may encompass multiple different types of malicious input or web page structures that can trigger the flawed URL rewriting behavior. This weakness is categorized under CWE-79 as a Cross-Site Scripting vulnerability, specifically involving improper neutralization of input during web page generation, and aligns with ATT&CK technique T1059.007 for script-based attacks targeting web browsers.
The operational impact of this vulnerability extends beyond simple data theft or session hijacking, as it can enable more sophisticated attacks such as unauthorized financial transactions, account takeovers, or data exfiltration through compromised form submissions. Users accessing malicious websites through Safari versions before 6.0.5 could unknowingly trigger form submissions that perform actions like changing account settings, transferring funds, or submitting personal information to attacker-controlled endpoints. The vulnerability's persistence across multiple Safari releases demonstrates a significant gap in the browser's security validation mechanisms, particularly in how the XSS Auditor handles URL parsing and rewriting. Organizations relying on Safari as their primary browser for web applications or internal systems face increased risk of successful phishing attacks or drive-by downloads that exploit this weakness. The vulnerability also undermines user trust in browser security features, as users may believe they are protected by the XSS Auditor when in fact malicious code can bypass these protections through the URL rewriting flaw. This particular vulnerability highlights the critical importance of maintaining up-to-date browser software and demonstrates how seemingly minor flaws in security components can have substantial real-world implications for user security and privacy.
Mitigation strategies for this vulnerability primarily focus on immediate software updates to Safari 6.0.5 or later versions where Apple has addressed the URL rewriting implementation within the XSS Auditor. System administrators should implement comprehensive browser update policies that ensure all users maintain current versions of Safari and other web browsers. Additionally, organizations can deploy web application firewalls or content filtering solutions that can detect and block malicious form submission patterns, though these solutions represent compensating controls rather than direct fixes. The vulnerability underscores the importance of regular security assessments of browser security features and highlights the need for organizations to maintain awareness of browser-specific vulnerabilities that may affect their security posture. Users should be educated about the risks of visiting untrusted websites and the importance of keeping their browsers updated, as this vulnerability could be exploited through social engineering attacks that lure users to malicious websites. Security teams should also consider implementing browser security policies that disable potentially dangerous features or enforce stricter content security policies to reduce the attack surface available to exploit this class of vulnerability.