CVE-2021-37786 in COVID Certificate App
Summary
by MITRE • 09/27/2021
Certain Federal Office of Information Technology Systems and Telecommunication FOITT products are affected by improper handling of exceptional conditions. This affects COVID Certificate App IOS 2.2.0 and below affected, patch in progress and COVID Certificate Check App IOS 2.2.0 and below affected, patch in progress. A denial of service (physically proximate) could be caused by scanning a crafted QR code.
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Analysis
by VulDB Data Team • 10/02/2021
The vulnerability identified as CVE-2021-37786 represents a critical flaw in Federal Office of Information Technology Systems and Telecommunication FOITT products, specifically impacting mobile applications designed for COVID certificate verification. This issue stems from inadequate exception handling mechanisms within the affected software components, creating a pathway for malicious actors to exploit the system through crafted input vectors. The vulnerability affects both the COVID Certificate App iOS version 2.2.0 and earlier, as well as the COVID Certificate Check App iOS version 2.2.0 and earlier, indicating a widespread impact across the mobile verification ecosystem. The technical nature of this flaw places it squarely within the realm of improper exception handling, which is categorized under CWE-707 in the Common Weakness Enumeration framework, specifically addressing improper handling of exceptional conditions that can lead to system instability and service disruption.
The operational impact of this vulnerability manifests as a denial of service condition that can be triggered through physical proximity to the target device, making it particularly concerning for mobile applications that process sensitive health data. When users scan a specially crafted QR code, the application fails to properly handle the exceptional condition, leading to a system crash or service interruption that prevents legitimate certificate verification operations. This vulnerability operates at the intersection of mobile security and health data processing, where the attack vector requires physical proximity to the device, suggesting that the flaw may be exploitable through targeted attacks or social engineering campaigns. The affected applications' reliance on QR code scanning for certificate validation creates a direct attack surface where malicious actors can craft QR codes that trigger the exception handling failure, effectively disabling the verification functionality.
From a cybersecurity perspective, this vulnerability demonstrates how mobile applications processing sensitive health information can be rendered unusable through seemingly simple input manipulation. The patch status indicates that vendors are aware of the issue and actively working on remediation, but the timeframe for deployment remains uncertain, leaving affected users vulnerable during the interim period. The combination of the denial of service nature with the physical proximity requirement places this vulnerability in the ATT&CK framework under the T1499 category for Network Denial of Service, though modified to include physical proximity as a vector. Security practitioners must consider this vulnerability when assessing risk in healthcare mobile applications, particularly those handling sensitive medical data where availability of verification services directly impacts public health operations. The flaw underscores the importance of robust exception handling in mobile applications, especially those dealing with critical infrastructure services, as inadequate error management can transform benign input processing into serious operational disruptions.
Organizations implementing these applications should prioritize immediate mitigation strategies including user education about avoiding suspicious QR codes, implementing network-level controls to prevent access to potentially malicious content, and monitoring for unusual patterns in certificate verification attempts. The vulnerability serves as a reminder that mobile applications handling health data require additional security considerations beyond traditional software vulnerabilities, particularly when they operate in environments where physical proximity can be leveraged as an attack vector. The affected applications' design for rapid deployment and widespread use during the pandemic means that the impact of this vulnerability extends beyond simple technical concerns to potentially affect public health operations and emergency response capabilities. Security teams should also consider the broader implications of this vulnerability within their incident response planning, as the physical proximity requirement may complicate traditional remote exploitation scenarios but introduces new challenges for user protection and system integrity.