CVE-2021-1553 in Small Business
Summary
by MITRE • 05/22/2021
Multiple vulnerabilities in the web-based management interface of certain Cisco Small Business 100, 300, and 500 Series Wireless Access Points could allow an authenticated, remote attacker to perform command injection attacks against an affected device. These vulnerabilities are due to improper validation of user-supplied input. An attacker could exploit these vulnerabilities by sending crafted HTTP requests to the web-based management interface of an affected system. A successful exploit could allow the attacker to execute arbitrary commands with root privileges on the device. To exploit these vulnerabilities, the attacker must have valid administrative credentials for the device.
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Analysis
by VulDB Data Team • 05/23/2021
The vulnerability identified as CVE-2021-1553 affects Cisco Small Business 100, 300, and 500 Series Wireless Access Points, representing a critical security flaw in the web-based management interface of these network devices. This vulnerability stems from insufficient input validation mechanisms that fail to properly sanitize user-supplied data, creating an avenue for command injection attacks. The affected devices are commonly deployed in small business environments where wireless network infrastructure requires management through web interfaces, making them attractive targets for cybercriminals seeking to compromise network security.
The technical exploitation of this vulnerability occurs through crafted HTTP requests sent to the web-based management interface of the affected access points. The improper validation of user input allows an authenticated attacker with valid administrative credentials to inject malicious commands that are then executed with root privileges on the device. This command injection flaw directly maps to CWE-77, which describes improper neutralization of special elements used in command execution contexts. The vulnerability essentially allows an attacker to bypass normal authentication mechanisms and execute arbitrary code at the highest privilege level available on the device, potentially enabling complete system compromise.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it provides attackers with root-level control over the affected wireless access points. This level of privilege allows for complete network disruption, data exfiltration, and potential lateral movement within the network infrastructure. Attackers could modify network configurations, disable wireless services, or establish persistent backdoors for continued access. The vulnerability's exploitation requires only valid administrative credentials, which suggests that it could be leveraged through credential theft, social engineering, or other initial compromise methods. This makes the vulnerability particularly dangerous in environments where administrative credentials may be weak or where credential reuse occurs across multiple systems.
Organizations should immediately implement mitigations including applying the latest security patches provided by Cisco, which address the input validation flaws in the web interface. Network segmentation and monitoring should be enhanced to detect suspicious HTTP request patterns that may indicate exploitation attempts. Access controls should be strengthened through multi-factor authentication implementation and regular credential rotation. The vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter, where adversaries use legitimate system tools to execute commands. Additionally, this vulnerability demonstrates the importance of input validation as outlined in OWASP Top 10 2021 category A03: Injection, emphasizing that proper sanitization of user inputs is critical to prevent command injection attacks that could lead to complete system compromise.