CVE-2018-0501 in apt
Summary
by MITRE
The mirror:// method implementation in Advanced Package Tool (APT) 1.6.x before 1.6.4 and 1.7.x before 1.7.0~alpha3 mishandles gpg signature verification for the InRelease file of a fallback mirror, aka mirrorfail.
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Analysis
by VulDB Data Team • 05/04/2023
The vulnerability identified as CVE-2018-0501 affects the Advanced Package Tool (APT) ecosystem, specifically targeting versions 1.6.x prior to 1.6.4 and 1.7.x prior to 1.7.0~alpha3. This issue manifests within the mirror:// method implementation where APT handles package repository mirrors, creating a critical security flaw that undermines the integrity verification process. The vulnerability is categorized under CWE-295 which specifically addresses improper certificate validation, making it particularly dangerous in package management contexts where trust and authenticity are paramount.
The technical flaw occurs when APT attempts to verify the InRelease file from a fallback mirror, which is a mechanism designed to provide alternative package sources when the primary mirror becomes unavailable. During this process, the system fails to properly validate GPG signatures for the InRelease file, allowing potentially malicious actors to exploit this weakness. The mirrorfail condition specifically arises when APT falls back to an alternative mirror, and the signature verification process becomes bypassed or weakened, enabling attackers to inject malicious packages or manipulate repository metadata. This behavior violates fundamental security principles of package verification and trust establishment.
The operational impact of this vulnerability is severe as it can lead to arbitrary code execution, package tampering, and supply chain attacks within systems that rely on APT for package management. Attackers could exploit this weakness by compromising a fallback mirror or by manipulating the mirror selection process to redirect users to malicious repositories. The vulnerability essentially undermines the security model of APT by allowing unauthenticated or improperly authenticated repository metadata to be accepted, potentially leading to privilege escalation, system compromise, or data exfiltration. Organizations using affected APT versions face significant risk during package installation and update processes.
Mitigation strategies for this vulnerability include immediate upgrade to APT versions 1.6.4 or 1.7.0~alpha3 and later, which contain the necessary patches to properly handle GPG signature verification for fallback mirrors. System administrators should also implement additional verification measures such as manually checking repository fingerprints, using trusted mirror lists, and monitoring package installation logs for suspicious activity. From an ATT&CK framework perspective, this vulnerability maps to techniques involving package management tampering and supply chain compromise, emphasizing the need for defensive measures at multiple layers of the attack chain. Organizations should also consider implementing network-level controls to restrict access to untrusted mirrors and establish robust monitoring protocols to detect anomalous package installation patterns that could indicate exploitation attempts.