CVE-2020-16147 in AccessLog
Summary
by MITRE
The login page in Telmat AccessLog <= 6.0 (TAL_20180415) allows an attacker to get root shell access via Unauthenticated code injection over the network.
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Analysis
by VulDB Data Team • 09/24/2020
The vulnerability identified as CVE-2020-16147 represents a critical security flaw in Telmat AccessLog version 6.0 and earlier, specifically within its login page implementation. This vulnerability stems from inadequate input validation and sanitization mechanisms that permit unauthenticated code injection attacks, creating a pathway for remote attackers to execute arbitrary commands on the affected system. The flaw exists in the authentication handling process where user-supplied input is not properly filtered or escaped before being processed by the application, allowing malicious payloads to be interpreted as executable code rather than mere data.
The technical exploitation of this vulnerability follows a pattern consistent with command injection attacks categorized under CWE-77 and CWE-94, where attacker-controlled input is directly incorporated into system commands without proper sanitization. The vulnerability specifically affects the login page functionality, which typically processes user credentials and other authentication parameters. When an attacker submits malicious input through the login form, the application fails to validate or sanitize this input properly, enabling the execution of arbitrary shell commands with the privileges of the web application user. Given that the application likely runs with elevated privileges to manage access logs and system resources, successful exploitation can result in complete system compromise.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it provides attackers with root shell access to the underlying system. This level of access allows adversaries to execute privileged commands, modify system files, install persistent backdoors, and potentially escalate their privileges further within the network infrastructure. The unauthenticated nature of the attack means that no prior credentials are required to exploit the vulnerability, making it particularly dangerous for systems that are publicly accessible or deployed in environments with limited network segmentation. Organizations using Telmat AccessLog versions prior to 6.1 may find their entire logging infrastructure compromised, potentially leading to data exfiltration, system disruption, and lateral movement within the network.
Mitigation strategies for CVE-2020-16147 should prioritize immediate patching of affected systems to the latest available version of Telmat AccessLog, which includes proper input validation and sanitization measures. Network administrators should implement additional protective measures such as firewall rules to restrict access to the login page and monitoring systems to detect anomalous login attempts or command execution patterns. The principle of least privilege should be enforced by running the application with minimal required permissions and implementing proper input filtering mechanisms that align with ATT&CK technique T1059.001 for command and scripting interpreter. Organizations should also conduct thorough security assessments of their logging infrastructure and consider implementing intrusion detection systems to identify potential exploitation attempts, as the vulnerability's impact can be devastating to system integrity and security posture.