CVE-2021-24656 in Simple Social Media Share Buttons Plugin
Summary
by MITRE • 10/11/2021
The Simple Social Media Share Buttons WordPress plugin before 3.2.4 does not escape the Share Title settings before outputting it in the frontend pages or posts (depending on the settings used), allowing high privilege users to perform Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed.
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Analysis
by VulDB Data Team • 10/14/2021
The vulnerability CVE-2021-24656 affects the Simple Social Media Share Buttons WordPress plugin, specifically versions prior to 3.2.4, presenting a critical cross-site scripting risk that undermines web application security. This flaw resides in the plugin's handling of user-provided content within the Share Title settings, where the plugin fails to properly sanitize or escape output before rendering it on frontend pages or posts. The vulnerability is particularly concerning because it allows attackers with high privilege user accounts to execute malicious scripts in the context of other users' browsers, even when the WordPress installation has restricted the unfiltered_html capability, which typically prevents such attacks by limiting direct html injection.
The technical nature of this vulnerability aligns with CWE-79, which describes cross-site scripting flaws occurring when untrusted data is sent to a web browser without proper validation or escaping. The flaw specifically manifests when the plugin processes Share Title settings that contain potentially malicious script code, which then gets executed in users' browsers when they view pages or posts containing these settings. Attackers can leverage this vulnerability by crafting malicious Share Title values containing script tags or other malicious code that will execute when the page loads, potentially stealing session cookies, performing unauthorized actions, or redirecting users to malicious sites.
The operational impact of this vulnerability extends beyond simple script execution, as it represents a significant security compromise that can enable more sophisticated attacks within the WordPress environment. High privilege users, such as administrators or editors, can exploit this vulnerability to inject malicious code that persists across multiple user sessions, potentially allowing for complete account takeover or data exfiltration. The attack vector is particularly dangerous because it operates within the legitimate plugin functionality, making it harder to detect through standard security monitoring systems. This vulnerability can be exploited in various contexts including blog posts, pages, or any content where the social share buttons are displayed, creating multiple attack surfaces for potential exploitation.
Mitigation strategies for CVE-2021-24656 require immediate plugin updates to version 3.2.4 or later, which contains the necessary escaping and sanitization fixes. Organizations should also implement additional security measures including regular security audits of installed plugins, monitoring for unauthorized plugin modifications, and ensuring that only trusted users have high privilege accounts. The WordPress security framework recommends implementing Content Security Policy headers to provide additional protection against script injection attacks, while the ATT&CK framework categorizes this vulnerability under T1059.001 for command and scripting interpreter, specifically focusing on script injection techniques that leverage web application vulnerabilities. Organizations should also consider implementing web application firewalls and regular security scanning to detect and prevent exploitation attempts, as well as maintaining comprehensive backup and recovery procedures to quickly restore systems in case of successful compromise.