Ubuntu update for Linux kernel

1) NULL pointer dereference/Race condition

EUVDB-ID: #VU11852

Risk: Low

CVSSv4.0: 4.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2015-7550

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Exploit availability: No

Description

The vulnerability allows a local attacker to cause DoS condition on the target system.

The weakness in the keyctl_read_key function in security/keys/keyctl.c due to improper use of a semaphore. A local attacker can submit a specially crafted application that leverages a race condition between keyctl_revoke and keyctl_read calls, trigger NULL pointer dereference and cause the service o crash.

Mitigation

Update the affected packages

Ubuntu 12.04 LTS:

linux-image-3.2.0-99-generic-pae 3.2.0-99.139

linux-image-3.2.0-99-powerpc64-smp 3.2.0-99.139

linux-image-3.2.0-99-generic 3.2.0-99.139

linux-image-3.2.0-99-virtual 3.2.0-99.139

linux-image-3.2.0-99-highbank 3.2.0-99.139

linux-image-3.2.0-99-powerpc-smp 3.2.0-99.139

linux-image-3.2.0-99-omap 3.2.0-99.139

Vulnerable software versions

Ubuntu: 12.04

CPE2.3

• cpe:2.3:o:canonical:ubuntu:12.04:*:*:*:*:*:*:*

External links

https://www.ubuntu.com/usn/usn-2911-1/

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.