CVE-2016-7565 in Exponent
Summary
by MITRE
install/index.php in Exponent CMS 2.3.9 allows remote attackers to execute arbitrary commands via shell metacharacters in the sc array parameter.
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Analysis
by VulDB Data Team • 11/14/2022
The vulnerability identified as CVE-2016-7565 affects Exponent CMS version 2.3.9 and represents a critical remote code execution flaw that stems from improper input validation in the install/index.php file. This issue allows attackers to inject shell metacharacters into the sc array parameter, which then gets processed without adequate sanitization, creating a pathway for arbitrary command execution on the affected system. The flaw resides in the installation script's handling of user-supplied data, where the sc parameter is directly incorporated into shell commands without proper escaping or validation mechanisms.
The technical exploitation of this vulnerability follows a well-established pattern that aligns with CWE-77 and CWE-94 categories, which respectively address improper neutralization of special elements used in commands and execution of code from external input. Attackers can leverage this weakness by crafting malicious payloads containing shell metacharacters such as semicolons, ampersands, or backticks that get interpreted by the underlying shell when the sc array parameter is processed. This type of vulnerability falls under the ATT&CK technique T1059.001 for command and scripting interpreter, specifically targeting the use of shell commands in web applications.
The operational impact of CVE-2016-7565 is severe as it provides attackers with complete control over the affected system once successfully exploited. Remote code execution enables threat actors to install malware, establish backdoors, exfiltrate sensitive data, or use the compromised server as a launch point for further attacks within the network. The vulnerability is particularly dangerous because it exists in the installation script, meaning that exploitation can occur during the initial setup phase of the CMS, potentially affecting organizations before they have properly configured security measures. Additionally, since the flaw is present in the core installation process, it affects all installations regardless of subsequent security hardening efforts.
Mitigation strategies for this vulnerability require immediate action including applying the vendor-provided patch or upgrade to Exponent CMS version 2.3.10 or later, which addresses the input validation issues in the install/index.php file. Organizations should also implement network-level protections such as firewall rules that restrict access to installation scripts and administrative interfaces until the vulnerability is resolved. Input sanitization should be enforced through proper escaping of shell metacharacters and validation of all user-supplied parameters. Security monitoring should be enhanced to detect unusual patterns in system command execution and parameter handling within web applications. The remediation process should include disabling or removing the installation script from production environments after successful installation, as this vulnerability specifically targets the installation phase of the CMS deployment.