CVE-2020-15262 in webpack-subresource-integrity
Summary
by MITRE • 10/20/2020
In webpack-subresource-integrity before version 1.5.1, all dynamically loaded chunks receive an invalid integrity hash that is ignored by the browser, and therefore the browser cannot validate their integrity. This removes the additional level of protection offered by SRI for such chunks. Top-level chunks are unaffected. This issue is patched in version 1.5.1.
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Analysis
by VulDB Data Team • 11/21/2020
The vulnerability identified as CVE-2020-15262 affects the webpack-subresource-integrity library, a critical component in web application security that implements Subresource Integrity (SRI) checks for dynamically loaded JavaScript chunks. This issue represents a significant weakening of security controls that developers rely upon to protect against malicious code injection in web applications. The vulnerability specifically targets versions prior to 1.5.1, where the library fails to properly generate integrity hashes for dynamically loaded chunks, creating a dangerous security gap in applications that depend on SRI for protection.
The technical flaw lies in the improper generation of cryptographic integrity hashes for dynamically loaded JavaScript chunks within webpack applications. When webpack-subresource-integrity processes these chunks, it produces invalid integrity values that browsers simply ignore during validation. This occurs because the library does not correctly calculate the hash values for dynamically loaded content, rendering the SRI mechanism ineffective for these particular resources. The vulnerability is classified as a weakness in the integrity verification process, aligning with CWE-347 - Improper Verification of Cryptographic Signature, and represents a failure in the security control implementation rather than a fundamental cryptographic flaw.
The operational impact of this vulnerability is substantial as it undermines the security assurances provided by Subresource Integrity, which is a critical defense mechanism against supply chain attacks and malicious code injection. When browsers encounter dynamically loaded chunks with invalid integrity hashes, they cannot verify that the code has not been tampered with during transit, leaving applications vulnerable to attacks such as man-in-the-middle attacks or compromised build systems. This issue particularly affects web applications that rely heavily on dynamic code loading patterns, where attackers could potentially inject malicious code into dynamically loaded chunks without detection. The vulnerability's impact is mitigated by the fact that top-level chunks remain unaffected, but this partial protection is insufficient for comprehensive security coverage.
The remediation for CVE-2020-15262 requires updating to version 1.5.1 or later of the webpack-subresource-integrity library, which addresses the hash generation algorithm and ensures proper integrity values are computed for all dynamically loaded chunks. Organizations should conduct thorough security assessments of their applications to identify all instances where webpack-subresource-integrity is implemented, particularly focusing on applications that utilize dynamic code loading features. This vulnerability demonstrates the importance of maintaining up-to-date security dependencies and highlights the potential for supply chain attacks to exploit seemingly minor issues in build tooling. The fix should be implemented as part of a broader security maintenance program that includes regular dependency updates and vulnerability scanning to prevent similar issues from compromising application security. The remediation aligns with ATT&CK technique T1059.006 for defending against malicious code injection and supports the broader security posture by maintaining proper cryptographic integrity verification for all application resources.