CVE-2018-25081 in Bitwarden
Summary
by MITRE • 03/09/2023
** DISPUTED ** Bitwarden through 2023.2.1 offers password auto-fill within a cross-domain IFRAME element. NOTE: the vendor's position is that there have been important legitimate cross-domain configurations (e.g., an apple.com IFRAME element on the icloud.com website) and that "Auto-fill on page load" is not enabled by default.
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Analysis
by VulDB Data Team • 04/27/2025
The vulnerability identified as CVE-2018-25081 relates to Bitwarden password manager version 2023.2.1 and earlier, where the software enables password auto-fill functionality within cross-domain iframe elements. This behavior creates a significant security concern as it allows password managers to automatically populate credentials across different domains, potentially exposing users to cross-site scripting attacks and credential leakage. The vulnerability exists in the context of web browser security models where cross-domain restrictions are designed to prevent unauthorized access to sensitive information between different websites. The implementation of auto-fill within iframes undermines the fundamental security boundary that separates domains, creating potential attack vectors for malicious actors who can leverage this functionality to harvest credentials from compromised or malicious websites.
The technical flaw stems from Bitwarden's decision to enable password auto-fill capabilities even when credentials are being entered within iframe contexts that belong to different domains than the parent page. This functionality operates outside the normal browser security boundaries that typically prevent such cross-domain interactions. According to the vendor's position, this behavior is not enabled by default, which suggests that it requires explicit user configuration or activation through specific settings. However, the mere existence of this capability within the software presents a risk as users may inadvertently enable it or may not fully understand the implications of cross-domain credential sharing. The vulnerability is classified under CWE-352, Cross-Site Request Forgery, and potentially CWE-200, Exposure of Sensitive Information, as it creates opportunities for unauthorized credential access and information disclosure.
The operational impact of this vulnerability extends beyond simple credential leakage, as it can enable sophisticated attacks such as credential harvesting through malicious iframes, session hijacking, and cross-site scripting exploitation. Attackers could embed malicious iframes on compromised websites that trigger Bitwarden's auto-fill functionality, potentially capturing credentials before they are even submitted to the legitimate target site. This capability also increases the attack surface for users who browse websites that may contain embedded iframes from other domains, particularly when those iframes are not properly secured or monitored. The risk is heightened when considering that many users may not be aware of the security implications of having auto-fill enabled in cross-domain contexts, making them unwitting participants in potential credential exposure scenarios.
The vendor's stance that legitimate cross-domain configurations exist, such as apple.com iframes on icloud.com, demonstrates an understanding that some cross-domain functionality is necessary for web usability and integration. However, this legitimate use case does not negate the security implications for password managers that enable auto-fill in such contexts. The recommended mitigations include ensuring that auto-fill functionality is disabled by default, implementing proper user education about the risks of cross-domain credential sharing, and providing clear warnings when auto-fill is detected in cross-domain iframe contexts. Security practitioners should also consider implementing browser security policies that restrict iframe access to password managers and ensure that any cross-domain functionality is properly audited for potential security implications. This vulnerability aligns with ATT&CK technique T1531, Account Access Removal, and T1071.004, Application Layer Protocol: DNS, as it can facilitate unauthorized access to accounts through compromised cross-domain interactions and may be used in conjunction with DNS-based attacks to further compromise user credentials. Organizations should review their Bitwarden configurations to ensure that auto-fill is not enabled in cross-domain contexts unless absolutely necessary and properly secured.