CVE-2018-0114

published 2018-01-04

CVE-2018-0114: A vulnerability in the Cisco node-jose open source library before 0.11.0 could allow an unauthenticated, remote attacker to re-sign tokens using a key that is…

Priority P2 67 high 7.5 CVSS 3.1

AV N AC L PR N UI N S U C N I H A N

EXPLOIT

A vulnerability in the Cisco node-jose open source library before 0.11.0 could allow an unauthenticated, remote attacker to re-sign tokens using a key that is embedded within the token. The vulnerability is due to node-jose following the JSON Web Signature (JWS) standard for JSON Web Tokens (JWTs). This standard specifies that a JSON Web Key (JWK) representing a public key can be embedded within the header of a JWS. This public key is then trusted for verification. An attacker could exploit this by forging valid JWS objects by removing the original signature, adding a new public key to the header, and then signing the object using the (attacker-owned) private key associated with the public key embedded in that JWS header.

Affected

2 ranges

Vendor	Product	Version range	Fixed in
cisco	node-jose	< 0.11.0	0.11.0
cisco	node-jose	>= 0 < 0.11.0	0.11.0

Detection & IOCs extracted from sources · hover to see the quote

version node-jose < 0.11.0↗

• → Inspect JWT/JWS headers for the presence of an embedded 'jwk' claim containing a public key (kty=RSA). Legitimate tokens should not carry a self-signed JWK in the header; its presence is a strong indicator of CVE-2018-0114 exploitation. ↗
• → Flag any JWT/JWS token whose decoded header contains a 'jwk' field with 'use':'sig', as the attacker embeds their own public key there to make the library trust and verify their forged signature. ↗
• → Monitor for the PoC-specific kid value '[email protected]' in JWT headers, which is a direct indicator of the public exploit (EDB-44324) being used. ↗

• · The vulnerability is rooted in node-jose blindly trusting the JWK embedded in the JWS header per the standard. Any deployment using node-jose < 0.11.0 for JWT verification is affected regardless of algorithm choice, as long as the library honours the embedded JWK. ↗
• · The PoC targets node-jose >= 8 (pre-0.11.0 fix). Ensure the patched version 0.11.0 or later is deployed; the fix removes implicit trust of the JWK embedded in the token header. ↗

CVSS provenance

nvd v3.1 7.5 HIGH CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

nvd v2.0 5.0 MEDIUM AV:N/AC:L/Au:N/C:N/I:P/A:N

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