CVE-2021-34682 in IRPF 2021
Summary
by MITRE • 06/13/2021
Receita Federal IRPF 2021 1.7 allows a man-in-the-middle attack against the update feature.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 06/18/2021
The vulnerability identified as CVE-2021-34682 affects the Receita Federal IRPF 2021 version 1.7 software, specifically targeting its update mechanism. This represents a critical security flaw that exposes users to man-in-the-middle attacks during software updates, potentially compromising the integrity and authenticity of the update process. The vulnerability stems from insufficient cryptographic protections and authentication mechanisms within the update feature, creating an attack surface that malicious actors can exploit to intercept and manipulate update communications.
The technical implementation of this vulnerability manifests through the absence of proper certificate validation and secure communication protocols during the update process. Attackers can position themselves between the user's system and the update server to intercept update packets, potentially injecting malicious code or redirecting users to compromised update sources. This flaw operates at the application layer and specifically affects the software's ability to verify the authenticity of update content, violating fundamental security principles of secure software distribution. The vulnerability aligns with CWE-319, which addresses the exposure of sensitive information through improper use of network protocols, and represents a clear violation of secure communication practices.
The operational impact of this vulnerability extends beyond simple software corruption, as it undermines the trust model of the entire software ecosystem. When users receive updates through a compromised channel, they unknowingly install potentially malicious code that could lead to complete system compromise, data exfiltration, or persistent backdoor access. The vulnerability particularly affects Brazilian tax filing software users who rely on official update mechanisms, creating a significant risk for individuals and organizations handling sensitive financial data. The attack vector enables adversaries to perform supply chain compromises, where legitimate update mechanisms become attack vectors for broader compromise operations, potentially affecting thousands of users simultaneously.
Mitigation strategies must address both immediate defensive measures and long-term architectural improvements. Organizations should implement network-level monitoring to detect unusual update traffic patterns and establish secure update channels with proper certificate pinning mechanisms. The software should be updated to include robust TLS validation, certificate verification, and secure update authentication protocols. Security controls should include network segmentation to prevent unauthorized access to update servers and implementation of secure software distribution practices aligned with NIST SP 800-53 security controls. Additionally, users should be educated about verifying update sources and implementing network security measures such as intrusion detection systems to monitor for suspicious update-related communications. The vulnerability demonstrates the critical importance of secure update mechanisms in maintaining software integrity and aligns with ATT&CK technique T1071.004 for application layer protocol tunneling and T1566 for credential harvesting through supply chain compromises.