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githubGitHub Advisory DatabaseGHSA-RVCW-F68W-8H8H
HistoryApr 19, 2021 - 3:00 p.m.

Padding Oracle Attack due to Observable Timing Discrepancy in jose-node-cjs-runtime

2021-04-1915:00:05
CWE-203
CWE-208
CWE-696
GitHub Advisory Database
github.com
50

CVSS2

4.3

Attack Vector

NETWORK

Attack Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

NONE

Availability Impact

NONE

AV:N/AC:M/Au:N/C:P/I:N/A:N

CVSS3

5.9

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

NONE

Availability Impact

NONE

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS

0.001

Percentile

51.2%

Impact

AES_CBC_HMAC_SHA2 Algorithm (A128CBC-HS256, A192CBC-HS384, A256CBC-HS512) decryption would always execute both HMAC tag verification and CBC decryption, if either failed JWEDecryptionFailed would be thrown. But a possibly observable difference in timing when padding error would occur while decrypting the ciphertext makes a padding oracle and an adversary might be able to make use of that oracle to decrypt data without knowing the decryption key by issuing on average 128*b calls to the padding oracle (where b is the number of bytes in the ciphertext block).

Patches

A patch was released which ensures the HMAC tag is verified before performing CBC decryption. The fixed versions are >=3.11.4.

Users should upgrade to ^3.11.4.

Credits

Thanks to Morgan Brown of Microsoft for bringing this up and Eva Sarafianou (@esarafianou) for helping to score this advisory.

Affected configurations

Vulners
Node
jose-node-cjs-runtime_projectjose-node-cjs-runtimeRange<3.11.4node.js
CPENameOperatorVersion
jose-node-cjs-runtimelt3.11.4

CVSS2

4.3

Attack Vector

NETWORK

Attack Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

NONE

Availability Impact

NONE

AV:N/AC:M/Au:N/C:P/I:N/A:N

CVSS3

5.9

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

NONE

Availability Impact

NONE

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS

0.001

Percentile

51.2%

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