CVE-2020-35129 in Mautic
Summary
by MITRE • 01/19/2021
Mautic before 3.2.4 is affected by stored XSS. An attacker with access to Social Monitoring, an application feature, could attack other users, including administrators. For example, an attacker could load an externally drafted JavaScript file that would allow them to eventually perform actions on the target user’s behalf, including changing the user’s password or email address or changing the attacker’s user role from a low-privileged user to an administrator account.
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Analysis
by VulDB Data Team • 02/15/2021
The vulnerability CVE-2020-35129 represents a critical stored cross-site scripting flaw in Mautic versions prior to 3.2.4, specifically within the Social Monitoring application feature. This vulnerability exposes organizations to significant security risks as it allows attackers with access to this particular module to inject malicious scripts that persist in the application's database and execute against other users who view the affected content. The flaw operates by permitting untrusted input to be stored and subsequently rendered without proper sanitization, creating a persistent vector for malicious code execution. The vulnerability is particularly concerning because it affects users with access to Social Monitoring, which often includes administrators and other privileged accounts, thereby amplifying the potential impact of exploitation.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding within the Social Monitoring feature's data handling processes. When users submit content through this interface, the application fails to properly sanitize or escape user-supplied data before storing it in the database. This stored data is then rendered in subsequent user sessions without proper context-aware encoding, allowing malicious JavaScript code to execute in the browser context of other users. The vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws, and demonstrates how insufficient data validation can create persistent security weaknesses. Attackers can leverage this vulnerability to load external JavaScript payloads that can manipulate user sessions, modify account credentials, or elevate privileges within the application.
The operational impact of CVE-2020-35129 extends beyond simple script execution, as it provides attackers with the capability to perform high-impact actions on behalf of compromised users. Successful exploitation could enable attackers to change user passwords, modify email addresses, or escalate privileges from low-privileged accounts to administrator roles, effectively granting them complete control over the Mautic instance. This type of vulnerability enables attackers to establish persistent access and maintain control over the application environment. The threat landscape for this vulnerability includes both external attackers who gain initial access through other means and internal threat actors with legitimate access to Social Monitoring functionality. The implications align with ATT&CK technique T1078.004, which covers valid accounts with elevated privileges, and T1566.001, covering spearphishing with a malicious attachment, as attackers can use this vulnerability to maintain access after initial compromise.
Organizations should prioritize immediate remediation by upgrading to Mautic version 3.2.4 or later, which includes proper input sanitization and output encoding measures to prevent stored XSS attacks. Additional mitigations should include implementing strict input validation for all user-supplied content, enforcing proper content security policies, and conducting regular security assessments of application features that handle external data. Network-level protections such as web application firewalls can provide additional defense-in-depth, while monitoring for suspicious content uploads in Social Monitoring modules can help detect potential exploitation attempts. Security teams should also implement principle of least privilege access controls for the Social Monitoring feature, limiting access to only those users who require this functionality for legitimate business purposes. Regular security training for administrators and users can help identify potential social engineering attempts that might lead to exploitation of this vulnerability.