Xen maintains the GTF{read,writ}ing bits as appropriate, to inform the guest that a grant is in use. A guest is expected not to modify the grant details while it is in use, whereas the guest is free to modify/reuse the grant entry when it is not in use. Under some circumstances, Xen will clear the status bits too early, incorrectly informing the guest that the grant is no longer in use. A guest may prematurely believe that a granted frame is safely private again, and reuse it in a way which contains sensitive information, while the domain on the far end of the grant is still using the grant. Xen 4.9, 4.8, 4.7, 4.6, and 4.5 are affected.
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Xen | Xen | 4.5.0 (including) | 4.5.0 (including) |
| Xen | Xen | 4.5.1 (including) | 4.5.1 (including) |
| Xen | Xen | 4.5.2 (including) | 4.5.2 (including) |
| Xen | Xen | 4.5.3 (including) | 4.5.3 (including) |
| Xen | Xen | 4.5.5 (including) | 4.5.5 (including) |
| Xen | Xen | 4.6.0 (including) | 4.6.0 (including) |
| Xen | Xen | 4.6.1 (including) | 4.6.1 (including) |
| Xen | Xen | 4.6.3 (including) | 4.6.3 (including) |
| Xen | Xen | 4.6.4 (including) | 4.6.4 (including) |
| Xen | Xen | 4.6.5 (including) | 4.6.5 (including) |
| Xen | Xen | 4.6.6 (including) | 4.6.6 (including) |
| Xen | Xen | 4.7.0 (including) | 4.7.0 (including) |
| Xen | Xen | 4.7.1 (including) | 4.7.1 (including) |
| Xen | Xen | 4.7.2 (including) | 4.7.2 (including) |
| Xen | Xen | 4.7.3 (including) | 4.7.3 (including) |
| Xen | Xen | 4.8.0 (including) | 4.8.0 (including) |
| Xen | Xen | 4.8.1 (including) | 4.8.1 (including) |
| Xen | Xen | 4.9.0 (including) | 4.9.0 (including) |
| Xen | Ubuntu | devel | * |
| Xen | Ubuntu | trusty | * |
| Xen | Ubuntu | xenial | * |
| Xen | Ubuntu | zesty | * |
There are many different kinds of mistakes that introduce information exposures. The severity of the error can range widely, depending on the context in which the product operates, the type of sensitive information that is revealed, and the benefits it may provide to an attacker. Some kinds of sensitive information include:
Information might be sensitive to different parties, each of which may have their own expectations for whether the information should be protected. These parties include:
Information exposures can occur in different ways:
It is common practice to describe any loss of confidentiality as an “information exposure,” but this can lead to overuse of CWE-200 in CWE mapping. From the CWE perspective, loss of confidentiality is a technical impact that can arise from dozens of different weaknesses, such as insecure file permissions or out-of-bounds read. CWE-200 and its lower-level descendants are intended to cover the mistakes that occur in behaviors that explicitly manage, store, transfer, or cleanse sensitive information.