Ubuntu update for gcc-5

1) Use of cryptographically weak PRNG

EUVDB-ID: #VU12267

Risk: Low

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2017-11671

CWE-ID: CWE-338 - Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

Exploit availability: No

Description

The vulnerability allows a remote attacker to obtain potentially sensitive information on the target system.

The weakness exists in the ix86_expand_builtin function in i386.c due to generating of instruction sequences that clobber the status flag of the RDRAND and RDSEED intrinsics before it can be read, potentially causing failures of these instructions to go unreported. A remote attacker can trigger less randomness in random number generation and gain access to potentially sensitive information.

Mitigation

Update the affected package gcc-5 to the latest version.

Vulnerable software versions

Ubuntu: 16.04

gdc-5 (Ubuntu package): before Ubuntu Pro (Infra-only)

gcj-5 (Ubuntu package): before Ubuntu Pro (Infra-only)

g++-5 (Ubuntu package): before Ubuntu Pro (Infra-only)

gfortran-5 (Ubuntu package): before Ubuntu Pro (Infra-only)

gcj-5-jre-headless (Ubuntu package): before Ubuntu Pro (Infra-only)

gccgo-5 (Ubuntu package): before Ubuntu Pro (Infra-only)

gccgo-6 (Ubuntu package): before Ubuntu Pro (Infra-only)

gcj-5-jdk (Ubuntu package): before Ubuntu Pro (Infra-only)

gcc-5 (Ubuntu package): before Ubuntu Pro (Infra-only)

gnat-5 (Ubuntu package): before Ubuntu Pro (Infra-only)

CPE2.3

• cpe:2.3:o:canonical:ubuntu:16.04:*:*:*:*:*:*:*
• cpe:2.3:a:canonical:gdc-5_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:a:canonical:gcj-5_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:a:canonical:g_plus_plus_-5_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:a:canonical:gfortran-5_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:a:canonical:gcj-5-jre-headless_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:a:canonical:gccgo-5_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:a:canonical:gccgo-6_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:a:canonical:gcj-5-jdk_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:a:canonical:gcc-5_ubuntu_package:*:*:*:*:*:ubuntu:*:*
• cpe:2.3:a:canonical:gnat-5_ubuntu_package:*:*:*:*:*:ubuntu:*:*

External links

https://ubuntu.com/security/notices/USN-5770-1

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

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