3.5 Low
CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
SINGLE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:M/Au:S/C:N/I:P/A:N
8.7 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
NONE
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
7 High
AI Score
Confidence
High
0.001 Low
EPSS
Percentile
23.8%
The vulnerability impacts only users of the IdTokenVerifier
class. The verify method in IdTokenVerifier
does not validate the signature before verifying the claims (e.g., iss, aud, etc.). Signature verification makes sure that the token’s payload comes from valid provider, not from someone else.
An attacker can provide a compromised token with modified payload like email or phone number. The token will pass the validation by the library. Once verified, modified payload can be used by the application.
If the application sends verified IdToken
to other service as is like for auth - the risk is low, because the backend of the service is expected to check the signature and fail the request.
Reporter: Tamjid al Rahat, contributor
The issue was fixed in the 1.33.3 version of the library
To reproduce, one needs to call the verify function with an IdToken instance that contains a malformed signature to successfully bypass the checks inside the verify function.
/** A default http transport factory for testing */
static class DefaultHttpTransportFactory implements HttpTransportFactory {
public HttpTransport create() {
return new NetHttpTransport();
}
}
// The below token has some modified bits in the signature
private static final String SERVICE_ACCOUNT_RS256_TOKEN_BAD_SIGNATURE =
"eyJhbGciOiJSUzI1NiIsImtpZCI6IjJlZjc3YjM4YTFiMDM3MDQ4NzA0MzkxNmFjYmYyN2Q3NG" +
"VkZDA4YjEiLCJ0eXAiOiJKV1QifQ.eyJhdWQiOiJodHRwczovL2V4YW1wbGUuY29tL2F1ZGllbm" +
"NlIiwiZXhwIjoxNTg3NjMwNTQzLCJpYXQiOjE1ODc2MjY5NDMsImlzcyI6InNvbWUgaXNzdWVy" +
"Iiwic3ViIjoic29tZSBzdWJqZWN0In0.gGOQW0qQgs4jGUmCsgRV83RqsJLaEy89-ZOG6p1u0Y26" +
"FyY06b6Odgd7xXLsSTiiSnch62dl0Lfi9D0x2ByxvsGOCbovmBl2ZZ0zHr1wpc4N0XS9lMUq5RJ" +
"QbonDibxXG4nC2zroDfvD0h7i-L8KMXeJb9pYwW7LkmrM_YwYfJnWnZ4bpcsDjojmPeUBlACg7tjjOgBFby" +
"QZvUtaERJwSRlaWibvNjof7eCVfZChE0PwBpZc_cGqSqKXv544L4ttqdCnm0NjqrTATXwC4gYx" +
"ruevkjHfYI5ojcQmXoWDJJ0-_jzfyPE4MFFdCFgzLgnfIOwe5ve0MtquKuv2O0pgvg";
IdTokenVerifier tokenVerifier =
new IdTokenVerifier.Builder()
.setClock(clock)
.setCertificatesLocation("https://www.googleapis.com/robot/v1/metadata/x509/integration-tests%40chingor-test.iam.gserviceaccount.com")
.setHttpTransportFactory(new DefaultHttpTransportFactory())
.build();
// verification will return true despite modified signature for versions <1.33.3
tokenVerifier.verify(IdToken.parse(GsonFactory.getDefaultInstance(), SERVICE_ACCOUNT_RS256_TOKEN_BAD_SIGNATURE));
Update to the version 1.33.3 or higher
If the library used indirectly or cannot be updated for any reason you can use similar IdToken verifiers provided by Google that already has signature verification. For example:
google-auth-library-java
google-api-java-client
Date reported: 12 Dec 2021
Date fixed: 13 Apr 2022
Date disclosed: 2 May 2022
If you have any questions or comments about this advisory:
CPE | Name | Operator | Version |
---|---|---|---|
com.google.oauth-client:google-oauth-client | lt | 1.33.3 |
github.com/advisories/GHSA-hw42-3568-wj87
github.com/googleapis/google-oauth-java-client/commit/c634ad4e31cac322bb1aa8a9feb0569749011bf0
github.com/googleapis/google-oauth-java-client/pull/872
github.com/googleapis/google-oauth-java-client/security/advisories/GHSA-hw42-3568-wj87
nvd.nist.gov/vuln/detail/CVE-2021-22573
3.5 Low
CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
SINGLE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:M/Au:S/C:N/I:P/A:N
8.7 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
NONE
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
7 High
AI Score
Confidence
High
0.001 Low
EPSS
Percentile
23.8%