CVE-2020-7982 in OpenWrt
Summary
by MITRE
An issue was discovered in OpenWrt 18.06.0 to 18.06.6 and 19.07.0, and LEDE 17.01.0 to 17.01.7. A bug in the fork of the opkg package manager before 2020-01-25 prevents correct parsing of embedded checksums in the signed repository index, allowing a man-in-the-middle attacker to inject arbitrary package payloads (which are installed without verification).
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Analysis
by VulDB Data Team • 03/17/2020
The vulnerability identified as CVE-2020-7982 represents a critical security flaw in the opkg package manager implementation within OpenWrt and LEDE firmware distributions. This issue affects versions ranging from OpenWrt 18.06.0 through 18.06.6 and 19.07.0, alongside LEDE 17.01.0 through 17.01.7, creating a widespread impact across numerous network device firmware deployments. The vulnerability stems from a parsing error in how the package manager handles embedded checksums within signed repository indexes, fundamentally undermining the integrity verification mechanisms that are essential for secure software distribution in embedded systems environments.
The technical flaw manifests in the forked opkg implementation where the software fails to correctly parse checksums embedded within signed repository indexes. This parsing failure creates a condition where the package manager cannot properly validate the integrity of downloaded packages, effectively allowing malicious actors to inject arbitrary package payloads into the distribution chain. The vulnerability operates at the core of package verification mechanisms, where the expected cryptographic signatures and checksum validation processes become ineffective due to the parsing bug. This weakness directly violates the principle of integrity protection that is fundamental to secure software distribution protocols, as outlined in CWE-347 for improper verification of cryptographic signatures.
The operational impact of this vulnerability is severe for network device administrators and security operators who rely on the integrity of package repositories for firmware updates. Attackers can exploit this weakness to perform man-in-the-middle attacks against package repositories, injecting malicious code or modified packages that will be installed without any verification by the target devices. This creates a persistent threat vector where compromised devices can be used for further network infiltration, data exfiltration, or as part of botnet formations. The vulnerability is particularly dangerous because it affects the update mechanism itself, meaning that even security patches intended to fix other vulnerabilities may be compromised during the update process, creating a cascading security risk.
The attack surface for this vulnerability extends across all devices running affected OpenWrt or LEDE versions that utilize the opkg package manager for software updates. This includes routers, wireless access points, network switches, and other embedded network devices that depend on these firmware distributions. The threat model aligns with ATT&CK technique T1068 for exploit for privilege escalation and T1566 for credential access through social engineering, as attackers can leverage this vulnerability to gain unauthorized access to device functionality. Organizations should prioritize immediate remediation through firmware updates, as the vulnerability exists in the core package management infrastructure and cannot be effectively mitigated through network-level controls alone. The fix requires updating to opkg versions released after January 25, 2020, which contain the corrected parsing logic for embedded checksums in repository indexes.
This vulnerability demonstrates the critical importance of maintaining secure package management systems in embedded environments, where the attack surface is often limited but the impact of compromise is significant. The flaw represents a failure in the security architecture of the package management system, where the integrity verification mechanisms are undermined by a parsing error rather than a cryptographic weakness. The vulnerability's persistence across multiple firmware versions indicates a systemic issue in the software supply chain that requires comprehensive review of all package management components. Security professionals should implement monitoring for suspicious package installations and maintain awareness of the specific attack patterns that could exploit this vulnerability, as the impact extends beyond immediate device compromise to potential network-wide security breaches.