Denial of service in Linux kernel

1) Divide By Zero

EUVDB-ID: #VU4198

Risk: Low

CVSSv4.0: 6.8 [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:A/U:Clear]

CVE-ID: CVE-2012-2100

CWE-ID: CWE-369 - Divide By Zero

Exploit availability: No

Description

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

The weakness exists due to divide-by-zero error in the ext4_fill_flex_info() function. By using a malformed ext4 filesystem containing a super block with a large FLEX_BG group size (aka s_log_groups_per_flex value), a local attacker can trigger kernel panic.

Successful exploitation of the vulnerability results in denial of service on the vulnerable system.

Note: the vulnerability was being actively exploited.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Linux kernel: 2.6.0 - 3.2.1

CPE2.3

• cpe:2.3:o:linux_foundation:linux_kernel:2.6.0:*:*:*:*:*:*:*
• cpe:2.3:o:linux_foundation:linux_kernel:2.6.1:*:*:*:*:*:*:*
• cpe:2.3:o:linux_foundation:linux_kernel:2.6.2:*:*:*:*:*:*:*
• cpe:2.3:o:linux_foundation:linux_kernel:2.6.3:*:*:*:*:*:*:*
• cpe:2.3:o:linux_foundation:linux_kernel:2.6.4:*:*:*:*:*:*:*
• cpe:2.3:o:linux_foundation:linux_kernel:2.6.5:*:*:*:*:*:*:*
• cpe:2.3:o:linux_foundation:linux_kernel:2.6.6:*:*:*:*:*:*:*
• cpe:2.3:o:linux_foundation:linux_kernel:2.6.7:*:*:*:*:*:*:*
• cpe:2.3:o:linux_foundation:linux_kernel:2.6.8:*:*:*:*:*:*:*
• cpe:2.3:o:linux_foundation:linux_kernel:2.6.8.1:*:*:*:*:*:*:*

External links

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d50f2ab6f050311dbf7b8f5501...

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. However, a fully functional exploit for this vulnerability is available.