cbcvebase.
CVE-2015-9235
published 2018-05-29

CVE-2015-9235: In jsonwebtoken node module before 4.2.2 it is possible for an attacker to bypass verification when a token digitally signed with an asymmetric key (RS/ES…

PriorityP357critical9.8CVSS 3.0
AVNACLPRNUINSUCHIHAH
EPSS
8.65%
94.5th percentile
In jsonwebtoken node module before 4.2.2 it is possible for an attacker to bypass verification when a token digitally signed with an asymmetric key (RS/ES family) of algorithms but instead the attacker send a token digitally signed with a symmetric algorithm (HS* family).

Affected

3 ranges
VendorProductVersion rangeFixed in
auth0jsonwebtoken< 4.2.24.2.2
auth0jsonwebtoken>= 0 < 4.2.24.2.2
hackeronejsonwebtoken_node_module

Detection & IOCsextracted from sources · hover to see the quote

  • An attacker exploiting this vulnerability sends a JWT token signed with a symmetric algorithm (HS* family) to a server that expects an asymmetric algorithm (RS/ES family), bypassing signature verification in jsonwebtoken node module before 4.2.2.
  • Inspect incoming JWT headers for algorithm confusion: flag tokens where the server is configured for RS*/ES* algorithms but the token's 'alg' header field specifies an HS* (HMAC) algorithm.
  • Review the fix commit at https://github.com/auth0/node-jsonwebtoken/commit/1bb584bc382295eeb7ee8c4452a673a77a68b687 to understand the verification logic change; audit verify.js for enforcement of expected algorithm at line ~62.
  • ·Only jsonwebtoken node module versions before 4.2.2 are vulnerable; version 7.2.1 and later are not affected due to algorithm enforcement in verify.js.
  • ·The vulnerability is only exploitable when the server is configured to accept tokens signed with asymmetric (RS/ES) algorithms but does not explicitly reject tokens presenting symmetric (HS*) algorithms in the header.

CVSS provenance

nvdv3.09.8CRITICALCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvdv2.07.5HIGHAV:N/AC:L/Au:N/C:P/I:P/A:P
vendor_redhat9.8CRITICAL
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