Vulnerability identifier: #VU2544

Vulnerability risk: High

CVSSv3.1: 9 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2015-7547

CWE-ID: CWE-121

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Glibc
Universal components / Libraries / Libraries used by multiple products

Vendor: GNU

Description
The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The weakness exists due to stack-based buffer overflow in in the (1) send_dg and (2) send_vc functions in the libresolv library. A remote attacker can use a crafted DNS response that triggers a call to the getaddrinfo function with the AF_UNSPEC or AF_INET6 address family, related to performing "dual A/AAAA DNS queries" and the libnss_dns.so.2 NSS module, cause memory corruption and execute arbitrary code.

Successful exploitation of the vulnerability may result in system compromise.

Mitigation
Update to version 2.23.

Vulnerable software versions

Glibc: 2.0 - 2.22

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External links
http://sourceware.org/bugzilla/show_bug.cgi?id=18665

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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. However, proof of concept for this vulnerability is available.