CVE-2021-22276 in free@home System Access Point
Summary
by MITRE • 09/24/2021
The vulnerability allows a successful attacker to bypass the integrity check of FW uploaded to the [email protected] System Access Point.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 10/02/2021
The vulnerability identified as CVE-2021-22276 represents a critical security flaw in the firmware update mechanism of the [email protected] System Access Point device. This weakness specifically targets the integrity verification process that should safeguard firmware installations against unauthorized modifications. The vulnerability allows malicious actors to bypass crucial security checks that normally ensure firmware integrity, potentially enabling the installation of malicious firmware versions that could compromise the entire system.
This flaw operates at the core of the device's firmware update protocol, where proper cryptographic signatures or hash verification mechanisms fail to properly validate the authenticity of firmware images before installation. The vulnerability stems from inadequate input validation and insufficient cryptographic controls within the update process, creating an exploitable condition that undermines the fundamental security posture of the device. According to CWE classification, this represents a weakness in the integrity verification mechanism, specifically categorized under CWE-347 Improper Verification of Cryptographic Signature, which directly relates to the failure to properly validate firmware integrity checks.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass complete system compromise and potential network infiltration. An attacker who successfully exploits this vulnerability can install malicious firmware that may provide persistent backdoor access, enable data exfiltration capabilities, or allow the device to function as a pivot point for further attacks within the network. The compromised system access point could serve as a launching platform for lateral movement, credential theft, or disruption of critical network services. This vulnerability directly maps to ATT&CK technique T1547.001 for Registry Run Keys / Startup Folder and T1068 for Exploitation for Privilege Escalation, as the compromised device could be used to establish persistent access or escalate privileges within the network environment.
Mitigation strategies for CVE-2021-22276 should prioritize immediate firmware updates from the vendor, which typically include enhanced cryptographic verification mechanisms and proper integrity checking procedures. Organizations must implement network monitoring to detect unauthorized firmware changes and establish strict access controls for system update processes. The vulnerability highlights the importance of maintaining up-to-date security patches and implementing robust change management procedures for network infrastructure devices. Additionally, network segmentation should be employed to limit the potential impact of a compromised access point, while continuous vulnerability assessments should be conducted to identify similar weaknesses in other network devices and systems. Security teams should also consider implementing firmware integrity monitoring solutions that can detect and alert on unauthorized firmware modifications, ensuring that the integrity check bypass is properly addressed through both immediate remediation and long-term security hardening measures.