CVE-2020-21786 in IBOS
Summary
by MITRE • 06/24/2021
In IBOS 4.5.4 Open, Arbitrary File Inclusion causes getshell via /system/modules/dashboard/controllers/CronController.php.
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Analysis
by VulDB Data Team • 06/26/2021
The vulnerability identified as CVE-2020-21786 affects IBOS 4.5.4 Open version and represents a critical arbitrary file inclusion flaw that can lead to remote code execution. This vulnerability resides within the CronController.php file located in the system/modules/dashboard/controllers/ directory of the IBOS application. The flaw stems from improper input validation and sanitization mechanisms that fail to adequately filter user-supplied parameters before processing them in file inclusion operations. Attackers can exploit this vulnerability by crafting malicious requests that manipulate the file inclusion logic to load and execute arbitrary files on the target system. The vulnerability specifically impacts the dashboard module's cron functionality where external inputs are directly incorporated into file path resolution without proper security controls.
The technical implementation of this vulnerability follows a classic arbitrary file inclusion pattern where user-controllable parameters are passed to file handling functions without adequate validation. The CWE-22 category applies here as the vulnerability involves improper limitation of a pathname to a restricted directory, allowing attackers to traverse file system paths and include unintended files. This flaw enables attackers to leverage the application's legitimate file inclusion mechanisms to load malicious payloads such as web shells or other harmful code. The exploitation typically involves sending crafted HTTP requests that manipulate parameters used in include or require statements within the CronController.php script, potentially leading to full system compromise.
The operational impact of CVE-2020-21786 extends beyond simple code execution to encompass complete system compromise and data breach potential. Successful exploitation allows attackers to execute arbitrary commands on the target server with the privileges of the web application user, potentially leading to persistent access, privilege escalation, and lateral movement within the network. The vulnerability can be leveraged to establish backdoors, exfiltrate sensitive data, or deploy additional malware. Organizations using IBOS 4.5.4 Open are particularly vulnerable as the flaw affects core system functionality and can be exploited without authentication, making it an attractive target for automated attacks. The attack surface is further expanded through the dashboard module's integration with various system components, potentially allowing for privilege escalation attacks and access to sensitive administrative functions.
Mitigation strategies for CVE-2020-21786 should focus on immediate patching of the affected IBOS version to the latest secure release that addresses the file inclusion vulnerability. Organizations should implement strict input validation and sanitization measures to prevent malicious parameters from reaching file inclusion functions, following the principle of least privilege for web application components. Network segmentation and firewall rules can help limit access to vulnerable endpoints, while web application firewalls should be configured to detect and block suspicious file inclusion patterns. Regular security audits and code reviews should be conducted to identify similar vulnerabilities in other application modules. The ATT&CK framework's T1059.007 technique for execution via scripting and T1566.001 for initial access through web application attacks should be considered when developing defensive strategies. Additionally, implementing proper logging and monitoring of file access patterns can help detect exploitation attempts and provide forensic evidence for incident response activities.