CVE-2017-8308 in Avast
Summary
by MITRE
In Avast Antivirus before v17, an unprivileged user (and thus malware or a virus) can mark an arbitrary process as Trusted from the perspective of the Avast product. This bypasses the Self-Defense feature of the product, opening a door to subsequent attack on many of its components.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 12/21/2020
The vulnerability identified as CVE-2017-8308 represents a critical privilege escalation flaw within Avast Antivirus software versions prior to v17. This security weakness allows unprivileged users to manipulate the antivirus's trust mechanisms, effectively granting malicious actors the ability to mark any process as trusted within the Avast ecosystem. The vulnerability fundamentally undermines the core security architecture of the antivirus solution by compromising its ability to distinguish between legitimate and malicious processes.
The technical implementation of this flaw lies in the improper handling of process trust relationships within Avast's security framework. Attackers can exploit this weakness to elevate their privileges and bypass the Self-Defense feature, which is designed to prevent malicious software from interfering with antivirus operations. This capability enables adversaries to manipulate the antivirus's behavior and potentially gain deeper system access. The vulnerability operates at the kernel level or through privileged system interfaces, allowing unauthorized users to modify trust relationships that should be restricted to administrator-level access. From a cybersecurity perspective, this represents a severe violation of the principle of least privilege and demonstrates a critical failure in access control mechanisms.
The operational impact of CVE-2017-8308 extends far beyond simple privilege escalation, creating multiple attack vectors for sophisticated adversaries. Once an attacker successfully marks a process as trusted, they can effectively disable or bypass numerous security components within Avast, including real-time protection, file scanning, and behavioral monitoring features. This vulnerability enables attackers to maintain persistence within the system while evading detection by the very security software designed to protect against such threats. The implications are particularly severe because the affected antivirus software is widely deployed across enterprise and consumer environments, potentially exposing thousands of systems to coordinated attacks. The vulnerability also creates opportunities for lateral movement within networks, as attackers can use the compromised antivirus to gain access to other systems or escalate their privileges further.
Mitigation strategies for CVE-2017-8308 require immediate software updates to Avast version 17 or later, which address the underlying trust management flaw. Organizations should implement comprehensive monitoring of process trust relationships and establish strict access controls for antivirus configuration. Security teams should also deploy additional layers of protection including endpoint detection and response solutions, network monitoring tools, and regular vulnerability assessments to identify potential exploitation attempts. From a compliance perspective, this vulnerability aligns with CWE-276, which addresses improper privileges, and maps to attack techniques in the MITRE ATT&CK framework under privilege escalation and defense evasion tactics. Organizations must also consider implementing principle of least privilege policies and regular security audits to prevent similar vulnerabilities from being exploited in other security products. The incident underscores the critical importance of secure coding practices and proper access control implementation in security software, particularly in anti-virus and endpoint protection solutions.