CVE-2020-13822 in Elliptic Package
Summary
by MITRE
The Elliptic package 6.5.2 for Node.js allows ECDSA signature malleability via variations in encoding, leading '\0' bytes, or integer overflows. This could conceivably have a security-relevant impact if an application relied on a single canonical signature.
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Analysis
by VulDB Data Team • 10/16/2024
The CVE-2020-13822 vulnerability affects the Elliptic package version 6.5.2 in Node.js environments and represents a critical flaw in elliptic curve digital signature algorithm implementation. This vulnerability stems from the package's handling of ECDSA signatures where variations in encoding methods, including the presence of null bytes, or integer overflow conditions can produce multiple valid signatures for the same message. The flaw specifically targets the canonical signature requirements that cryptographic systems depend upon for security guarantees. When applications assume that ECDSA signatures will be unique and canonical, this malleability issue creates potential security risks that could be exploited by adversaries.
The technical implementation of this vulnerability resides in how the Elliptic package processes and validates elliptic curve signatures, particularly when dealing with different encoding formats such as DER (Distinguished Encoding Rules) versus raw signature components. The presence of null bytes or integer overflows during signature generation or verification processes can result in signature variations that maintain cryptographic validity while altering the signature representation. This behavior directly violates the expected canonical format requirements for ECDSA signatures, where each message should produce exactly one standardized signature representation. The vulnerability aligns with CWE-184, which addresses incomplete definition of canonical form in cryptographic operations, and represents a failure in proper signature normalization.
The operational impact of this vulnerability extends beyond simple signature verification issues, as it can potentially compromise systems that depend on signature uniqueness for security mechanisms such as transaction validation in blockchain applications, certificate validation processes, or any system requiring canonical signature representations. Applications using the affected Elliptic package may experience unexpected behavior when processing signatures, particularly in systems where signature malleability could be exploited to manipulate transaction states, bypass validation checks, or create confusion in signature-based authentication systems. The vulnerability demonstrates how seemingly minor encoding variations can have significant security implications in cryptographic implementations.
Organizations should immediately update to Elliptic package versions that address this malleability issue, typically version 6.5.3 or later, which implements proper canonical signature handling. System administrators should conduct comprehensive vulnerability assessments to identify applications that depend on the affected package and ensure proper patching across all environments. Security teams should monitor for potential exploitation attempts that might leverage signature malleability in systems where canonical signatures are assumed. The remediation process should include not only updating the package but also validating that existing signature validation logic properly handles edge cases and that applications are not relying on non-canonical signature representations. This vulnerability highlights the importance of proper cryptographic implementation practices and adherence to established security standards such as those defined in NIST SP 800-78 for digital signatures and the ATT&CK framework's cryptographic operations techniques that emphasize the need for robust signature validation mechanisms.