Handlebars before 4.4.5 allows Regular Expression Denial of Service (ReDoS) because of eager matching. The parser may be forced into an endless loop while processing crafted templates. This may allow attackers to exhaust system resources.
Weakness
The product does not properly control the allocation and maintenance of a limited resource.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Handlebars | Handlebarsjs | 4.0.0 (including) | 4.4.5 (excluding) |
| Red Hat OpenShift Container Platform 4.6 | RedHat | openshift4/ose-logging-kibana6:v4.6.0-202106181629.p0.git.40f3e72 | * |
| Red Hat Quay 3 | RedHat | quay/quay-rhel8:v3.6.0-62 | * |
| Red Hat Virtualization Engine 4.4 | RedHat | ovirt-web-ui-0:1.6.5-1.el8ev | * |
| RHPAM 7.13.1 async | RedHat | handlebars | * |
| Libjs-handlebars | Ubuntu | trusty | * |
| Node-handlebars | Ubuntu | bionic | * |
| Node-handlebars | Ubuntu | trusty | * |
| Node-handlebars | Ubuntu | upstream | * |
Potential Mitigations
Mitigation of resource exhaustion attacks requires that the target system either:
The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.
The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.
Related Attack Patterns
- https://cwe.mitre.org/data/definitions/147.html
- https://cwe.mitre.org/data/definitions/227.html
- https://cwe.mitre.org/data/definitions/492.html
References
- https://github.com/handlebars-lang/handlebars.js/commit/8d5530ee2c3ea9f0aee3fde310b9f36887d00b8b
- https://snyk.io/vuln/SNYK-JS-HANDLEBARS-480388
- https://www.npmjs.com/advisories/1300
- https://github.com/handlebars-lang/handlebars.js/commit/8d5530ee2c3ea9f0aee3fde310b9f36887d00b8b
- https://snyk.io/vuln/SNYK-JS-HANDLEBARS-480388
- https://www.npmjs.com/advisories/1300