A race condition issue leading to a use-after-free flaw was found in the way the raw packet sockets implementation in the Linux kernel networking subsystem handled synchronization while creating the TPACKET_V3 ring buffer. A local user able to open a raw packet socket (requires the CAP_NET_RAW capability) could use this flaw to elevate their privileges on the system.
Find out more about CVE-2016-8655 from the MITRE CVE dictionary dictionary and NIST NVD.
This issue does not affect Red Hat Enterprise Linux 5 and 6.
This issue does affect Red Hat Enterprise Linux 7 and Red Hat Enterprise MRG 2. Future updates for the respective releases will address this issue.
In a default or common use of Red Hat Enterprise Linux 7 this issue does not allow an unprivileged local user elevate their privileges on the system.
In order to exploit this issue the attacker needs CAP_NET_RAW capability, which needs to be granted by the administrator to the attacker's account. Since Red Hat Enterprise Linux 7 does not have unprivileged user namespaces enabled by default, local unprivileged users also cannot abuse namespaces to grant this capability to themselves and elevate their privileges.
| Base Score | 6.6 |
|---|---|
| Base Metrics | AV:L/AC:M/Au:S/C:C/I:C/A:C |
| Access Vector | Local |
| Access Complexity | Medium |
| Authentication | Single |
| Confidentiality Impact | Complete |
| Integrity Impact | Complete |
| Availability Impact | Complete |
| CVSS3 Base Score | 7 |
|---|---|
| CVSS3 Base Metrics | CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H |
| Attack Vector | Local |
| Attack Complexity | High |
| Privileges Required | Low |
| User Interaction | None |
| Scope | Unchanged |
| Confidentiality | High |
| Integrity Impact | High |
| Availability Impact | High |
Find out more about Red Hat support for the Common Vulnerability Scoring System (CVSS).
| Platform | Errata | Release Date |
|---|---|---|
| Red Hat Enterprise Linux 7 (kernel) | RHSA-2017:0386 | 2017-03-02 |
| Red Hat Enterprise Linux for Real Time for NFV (v. 7) (kernel-rt) | RHSA-2017:0387 | 2017-03-02 |
| Red Hat MRG Grid for RHEL 6 Server v.2 (kernel-rt) | RHSA-2017:0402 | 2017-03-02 |
| Platform | Package | State |
|---|---|---|
| Red Hat Enterprise Linux 6 | kernel | Not affected |
| Red Hat Enterprise Linux 5 | kernel | Not affected |
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