Helm is a tool for managing Charts. Charts are packages of pre-configured Kubernetes resources. Fuzz testing, provided by the CNCF, identified input to functions in the strvals package that can cause an out of memory panic. The strvals package contains a parser that turns strings in to Go structures. The strvals package converts these strings into structures Go can work with. Some string inputs can cause array data structures to be created causing an out of memory panic. Applications that use the strvals package in the Helm SDK to parse user supplied input can suffer a Denial of Service when that input causes a panic that cannot be recovered from. The Helm Client will panic with input to --set, --set-string, and other value setting flags that causes an out of memory panic. Helm is not a long running service so the panic will not affect future uses of the Helm client. This issue has been resolved in 3.9.4. SDK users can validate strings supplied by users wont create large arrays causing significant memory usage before passing them to the strvals functions.
The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Helm | Helm | 3.0.0 (including) | 3.9.4 (excluding) |
Limited resources include memory, file system storage, database connection pool entries, and CPU. If an attacker can trigger the allocation of these limited resources, but the number or size of the resources is not controlled, then the attacker could cause a denial of service that consumes all available resources. This would prevent valid users from accessing the product, and it could potentially have an impact on the surrounding environment. For example, a memory exhaustion attack against an application could slow down the application as well as its host operating system. There are at least three distinct scenarios which can commonly lead to resource exhaustion:
Resource exhaustion problems are often result due to an incorrect implementation of the following situations:
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.