A flaw was found in all released versions of m2crypto, where they are vulnerable to Bleichenbacher timing attacks in the RSA decryption API via the timed processing of valid PKCS#1 v1.5 Ciphertext. The highest threat from this vulnerability is to confidentiality.
Covert timing channels convey information by modulating some aspect of system behavior over time, so that the program receiving the information can observe system behavior and infer protected information.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| M2crypto | M2crypto_project | * | * |
| Red Hat Virtualization Engine 4.4 | RedHat | org.ovirt.engine-root-0:4.4.5.9-1 | * |
| M2crypto | Ubuntu | bionic | * |
| M2crypto | Ubuntu | groovy | * |
| M2crypto | Ubuntu | hirsute | * |
| M2crypto | Ubuntu | impish | * |
| M2crypto | Ubuntu | kinetic | * |
| M2crypto | Ubuntu | lunar | * |
| M2crypto | Ubuntu | mantic | * |
| M2crypto | Ubuntu | trusty | * |
| M2crypto | Ubuntu | xenial | * |
In some instances, knowing when data is transmitted between parties can provide a malicious user with privileged information. Also, externally monitoring the timing of operations can potentially reveal sensitive data. For example, a cryptographic operation can expose its internal state if the time it takes to perform the operation varies, based on the state. Covert channels are frequently classified as either storage or timing channels. Some examples of covert timing channels are the system’s paging rate, the time a certain transaction requires to execute, and the time it takes to gain access to a shared bus.