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computer vulnerability alert CVE-2015-7547

glibc: buffer overflow of getaddrinfo

Synthesis of the vulnerability

An attacker, who owns a malicious DNS server, can reply with long data to a client application using the getaddrinfo() function of the glibc, in order to trigger a denial of service, and possibly to run code in the client application.
Impacted products: ArubaOS, Blue Coat CAS, Brocade Network Advisor, Brocade vTM, Cisco ASR, Cisco Catalyst, IOS XE Cisco, Nexus by Cisco, NX-OS, Cisco Prime Access Registrar, Cisco Prime DCNM, Secure ACS, Cisco CUCM, Cisco IP Phone, Cisco Wireless IP Phone, Cisco Wireless Controller, XenDesktop, PowerPath, Unisphere EMC, VNX Operating Environment, VNX Series, ExtremeXOS, BIG-IP Hardware, TMOS, Fedora, QRadar SIEM, Trinzic, NSM Central Manager, NSMXpress, McAfee Email Gateway, McAfee MOVE AntiVirus, VirusScan, McAfee Web Gateway, openSUSE, openSUSE Leap, Palo Alto Firewall PA***, PAN-OS, RealPresence Distributed Media Application, Polycom VBP, RHEL, ROX, RuggedSwitch, Slackware, SUSE Linux Enterprise Desktop, SLES, Synology DS***, Synology RS***, Ubuntu, Unix (platform) ~ not comprehensive, ESXi, VMware vSphere, VMware vSphere Hypervisor, WindRiver Linux.
Severity: 4/4.
Creation date: 16/02/2016.
Revision date: 17/02/2016.
Identifiers: 046146, 046151, 046153, 046155, 046158, 1977665, 478832, 479427, 479906, 480572, 480707, 480708, ARUBA-PSA-2016-001, BSA-2016-003, BSA-2016-004, CERTFR-2016-AVI-066, CERTFR-2016-AVI-071, CERTFR-2017-AVI-012, CERTFR-2017-AVI-022, cisco-sa-20160218-glibc, CTX206991, CVE-2015-7547, ESA-2016-020, ESA-2016-027, ESA-2016-028, ESA-2016-029, ESA-2016-030, FEDORA-2016-0480defc94, FEDORA-2016-0f9e9a34ce, JSA10774, KB #4858, openSUSE-SU-2016:0490-1, openSUSE-SU-2016:0510-1, openSUSE-SU-2016:0511-1, openSUSE-SU-2016:0512-1, PAN-SA-2016-0021, RHSA-2016:0175-01, RHSA-2016:0176-01, RHSA-2016:0225-01, SA114, SB10150, SOL47098834, SSA:2016-054-02, SSA-301706, SUSE-SU-2016:0470-1, SUSE-SU-2016:0471-1, SUSE-SU-2016:0472-1, SUSE-SU-2016:0473-1, USN-2900-1, VIGILANCE-VUL-18956, VMSA-2016-0002, VMSA-2016-0002.1, VN-2016-003.

Description of the vulnerability

The glibc library implements a DNS resolver (libresolv).

An application can thus call the getaddrinfo() function, which queries DNS servers. When the AF_UNSPEC type is used in the getaddrinfo() call, two DNS A and AAAA queries are sent simultaneously. However, this special case, and a case with AF_INET6 are not correctly managed, and lead to an overflow if the reply coming from the DNS server is larger than 2048 bytes.

An attacker, who owns a malicious DNS server, can therefore reply with large data to a client application using the getaddrinfo() function of the glibc, in order to trigger a denial of service, and possibly to run code in the client application.
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