jose is an npm library providing a number of cryptographic operations.
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
All major release versions have had a patch released which ensures the HMAC tag is verified before performing CBC decryption. The fixed versions are ^1.28.1 || ^2.0.5 || >=3.11.4.
Users should upgrade their v1.x dependency to ^1.28.1, their v2.x dependency to ^2.0.5, and their v3.x dependency 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.
The PBKDF2-based JWE key management algorithms expect a JOSE Header Parameter named p2c (PBES2 Count), which determines how many PBKDF2 iterations must be executed in order to derive a CEK wrapping key. The purpose of this parameter is to intentionally slow down the key derivation function in order to make password brute-force and dictionary attacks more expensive.
This makes the PBES2 algorithms unsuitable for situations where the JWE is coming from an untrusted source: an adversary can intentionally pick an extremely high PBES2 Count value, that will initiate a CPU-bound computation that may take an unreasonable amount of time to finish.
Impact
Under certain conditions (see below) it is possible to have the user's environment consume unreasonable amount of CPU time.
Affected users
The impact is limited only to users utilizing the JWE decryption APIs with symmetric secrets to decrypt JWEs from untrusted parties who do not limit the accepted JWE Key Management Algorithms (alg Header Parameter) using the keyManagementAlgorithms (or algorithms in v1.x) decryption option or through other means.
The PBKDF2-based JWE Key Management Algorithm Identifiers are
PBES2-HS256+A128KW
PBES2-HS384+A192KW
PBES2-HS512+A256KW
e.g.
const secret = new Uint8Array(16)
const jwe = '...' // JWE from an untrusted party
await jose.compactDecrypt(jwe, secret)
You are NOT affected if any of the following applies to you
Your code does not use the JWE APIs
Your code only produces JWE tokens
Your code only decrypts JWEs using an asymmetric JWE Key Management Algorithm (this means you're providing an asymmetric key object to the JWE decryption API)
Your code only accepts JWEs produced by trusted sources
Your code limits the accepted JWE Key Management Algorithms using the keyManagementAlgorithms decryption option not including any of the PBKDF2-based JWE key management algorithms
Patches
v1.28.2, v2.0.6, v3.20.4, and v4.9.2 releases limit the maximum PBKDF2 iteration count to 10000 by default. It is possible to adjust this limit with a newly introduced maxPBES2Count decryption option.
Workarounds
All users should be able to upgrade given all stable semver major release lines have had new a patch release introduced which limits the PBKDF2 iteration count to 10000 by default. This removes the ability to craft JWEs that would consume unreasonable amount of CPU time.
If users are unable to upgrade their required library version they have two options depending on whether they expect to receive JWEs using any of the three PBKDF2-based JWE key management algorithms.
they can use the keyManagementAlgorithms decryption option to disable accepting PBKDF2 altogether
they can inspect the JOSE Header prior to using the decryption API and limit the PBKDF2 iteration count (p2c Header Parameter)
For more information
If you have any questions or comments about this advisory:
This PR contains the following updates:
1.25.0
->1.28.2
GitHub Vulnerability Alerts
CVE-2021-29443
jose is an npm library providing a number of cryptographic operations.
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
All major release versions have had a patch released which ensures the HMAC tag is verified before performing CBC decryption. The fixed versions are
^1.28.1 || ^2.0.5 || >=3.11.4
.Users should upgrade their v1.x dependency to
^1.28.1
, their v2.x dependency to^2.0.5
, and their v3.x dependency 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.
CVE-2022-36083
The PBKDF2-based JWE key management algorithms expect a JOSE Header Parameter named
p2c
(PBES2 Count), which determines how many PBKDF2 iterations must be executed in order to derive a CEK wrapping key. The purpose of this parameter is to intentionally slow down the key derivation function in order to make password brute-force and dictionary attacks more expensive.This makes the PBES2 algorithms unsuitable for situations where the JWE is coming from an untrusted source: an adversary can intentionally pick an extremely high PBES2 Count value, that will initiate a CPU-bound computation that may take an unreasonable amount of time to finish.
Impact
Under certain conditions (see below) it is possible to have the user's environment consume unreasonable amount of CPU time.
Affected users
The impact is limited only to users utilizing the JWE decryption APIs with symmetric secrets to decrypt JWEs from untrusted parties who do not limit the accepted JWE Key Management Algorithms (
alg
Header Parameter) using thekeyManagementAlgorithms
(oralgorithms
in v1.x) decryption option or through other means.The PBKDF2-based JWE Key Management Algorithm Identifiers are
PBES2-HS256+A128KW
PBES2-HS384+A192KW
PBES2-HS512+A256KW
e.g.
You are NOT affected if any of the following applies to you
keyManagementAlgorithms
decryption option not including any of the PBKDF2-based JWE key management algorithmsPatches
v1.28.2
,v2.0.6
,v3.20.4
, andv4.9.2
releases limit the maximum PBKDF2 iteration count to10000
by default. It is possible to adjust this limit with a newly introducedmaxPBES2Count
decryption option.Workarounds
All users should be able to upgrade given all stable semver major release lines have had new a patch release introduced which limits the PBKDF2 iteration count to
10000
by default. This removes the ability to craft JWEs that would consume unreasonable amount of CPU time.If users are unable to upgrade their required library version they have two options depending on whether they expect to receive JWEs using any of the three PBKDF2-based JWE key management algorithms.
keyManagementAlgorithms
decryption option to disable accepting PBKDF2 altogetherp2c
Header Parameter)For more information
If you have any questions or comments about this advisory:
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