CVE-2007-6536 in Toolbar
Summary
by MITRE
The Custom Button Installer dialog in Google Toolbar 4 and 5 beta presents certain domain names in the (1) "Downloaded from" and (2) "Privacy considerations" sections without verifying domain names, which makes it easier for remote attackers to spoof domain names and trick users into installing malicious button XML files, as demonstrated by presenting www.google.com when the button was downloaded from an arbitrary site through an open redirector on www.google.com.
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Analysis
by VulDB Data Team • 08/02/2019
The vulnerability described in CVE-2007-6536 represents a critical security flaw in the Google Toolbar 4 and 5 beta versions that undermines user trust and system integrity through improper domain name validation. This issue specifically affects the Custom Button Installer dialog component which is responsible for handling the installation of custom toolbar buttons. The flaw stems from the absence of domain name verification mechanisms within the dialog's presentation logic, creating a pathway for malicious actors to manipulate the displayed information and deceive users into installing potentially harmful software.
The technical implementation of this vulnerability allows attackers to exploit the lack of validation by leveraging open redirectors or other web application flaws to present misleading domain information. When users encounter the Custom Button Installer dialog, they see domain names displayed in two critical sections: "Downloaded from" and "Privacy considerations" without any verification process. This means that even when a button is actually downloaded from a malicious third-party site, the installer can be configured to display legitimate domain names such as www.google.com, creating a false sense of security and trust. The vulnerability specifically demonstrates how an attacker could use an open redirector on www.google.com to make it appear as though a malicious button was downloaded from Google's official domain, exploiting user familiarity and trust in well-known brands.
The operational impact of this vulnerability extends beyond simple social engineering, as it creates a persistent attack vector that can be used to distribute malware through seemingly legitimate channels. Users who are accustomed to trusting Google's brand and security practices become vulnerable to attacks that exploit their expectations and trust relationships. The attack scenario becomes particularly dangerous because it combines technical exploitation with psychological manipulation, where users are more likely to proceed with installation when domain names appear to originate from trusted sources. This vulnerability essentially transforms the user interface into an attack surface that can be leveraged to bypass security controls and deliver malicious payloads through the toolbar installation process.
The security implications align with CWE-601 and CWE-346 vulnerability classifications, which address open redirect vulnerabilities and URL validation issues respectively. From an adversarial perspective, this vulnerability maps directly to ATT&CK technique T1195.001 which covers 'Supply Chain Compromise: Software Piracy' and T1059.001 which covers 'Command and Scripting Interpreter: PowerShell'. The flaw creates an environment where attackers can establish trust relationships with users while simultaneously executing malicious code, making it particularly effective for delivering trojans, keyloggers, or other malicious software through the toolbar installation process. Organizations and individual users who installed affected versions of Google Toolbar became vulnerable to targeted attacks that exploited their trust in Google's brand and security practices.
Mitigation strategies for this vulnerability should include immediate removal of affected Google Toolbar versions, implementation of domain validation checks in all user interface components that display external source information, and establishment of proper certificate validation procedures for software installation processes. System administrators should consider implementing network monitoring to detect unusual installation patterns and user behavior that might indicate successful exploitation attempts. Additionally, regular security audits should be conducted to ensure that all software components properly validate external information before presenting it to users, particularly in contexts where user trust and security decisions are influenced by displayed information. The vulnerability underscores the importance of defense in depth principles and the necessity of validating all information presented to users regardless of its source or apparent legitimacy.