Lack of JWT issuer and signer validation
The Amazon.ApplicationLoadBalancer.Identity.AspNetCore repo https://github.com/awslabs/aws-alb-identity-aspnetcore#validatetokensignature contains Middleware that can be used in conjunction with the Application Load Balancer (ALB) OpenId Connect integration and can be used in any ASP.NET https://dotnet.microsoft.com/apps/aspnet Core deployment scenario, including Fargate, EKS, ECS, EC2, and Lambda. In the JWT handling code, it performs signature validation but fails to validate the JWT issuer and signer identity. The signer omission, if combined with a scenario where the infrastructure owner allows internet traffic to the ALB targets (not a recommended configuration), can allow for JWT signing by an untrusted entity and an actor may be able to mimic valid OIDC-federated sessions to the ALB targets. The repository/package has been deprecated, is end of life, and is no longer supported. As a security best practice, ensure that your ELB targets (e.g. EC2 Instances, Fargate Tasks etc.) do not have public IP addresses. Ensure any forked or derivative code validate that the signer attribute in the JWT match the ARN of the Application Load Balancer that the service is configured to use.
- Published
- Oct 21, 2024
- Updated
- Jun 17, 2026
- EPSS
- 0.3% · 23th percentile
- CWE
- CWE-290
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Report tools
Action score
27
Monitor
Low priority for now.
- CVSS
- 27 / 40 · 6.9 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.3%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · AMZN
- 6.9
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
—
Versions reported by the vendor
Affected version ranges reported by the assigning authority (AMZN). Independent of NVD's CPE analysis and usually ahead of it.
Amazon Amazon.ApplicationLoadBalancer.Identity.AspNetCore Middleware
- allaffected
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- Integrity
- Availability
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- X
Weakness class (CWE)
CWE-290 · Authentication Bypass by SpoofingCVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Exploitation of Trusted IdentifiersCAPEC-21likelihood: High · High
- Exploiting Trust in ClientCAPEC-22likelihood: High · High
- Creating a Rogue Certification Authority CertificateCAPEC-459likelihood: Medium · Very High
- Web Services API Signature Forgery Leveraging Hash Function Extension WeaknessCAPEC-461High
- Signature SpoofCAPEC-473
- Signature Spoofing by MisrepresentationCAPEC-476likelihood: Low · High
- Session Credential Falsification through PredictionCAPEC-59likelihood: High · High
- Reusing Session IDs (aka Session Replay)CAPEC-60likelihood: High · High
ATT&CK techniques
- Masquerading: Invalid Code SignatureT1036.001
- Access Token ManipulationT1134
- Access Token Manipulation:Token Impersonation/TheftT1134.001
- Steal Application Access TokenT1528
- Steal Web Session CookieT1539
- Use Alternate Authentication Material:Web Session CookieT1550.004
- Subvert Trust Controls: Code SigningT1553.002
- Adversary-in-the-MiddleT1557
Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
- aws.amazon.com/security/security-bulletins/AWS-2024-012/
- github.com/awslabs/aws-alb-identity-aspnetcore/security/advisories/GHSA-5gh5-cc5m-q244
Vendor advisories and official records. Exploit/PoC links are deliberately left out.