nghttp2 ALTSVC Frame NULL Pointer Dereference Denial of Service Vulnerability [CVE-2018-1000168]
CVE Number – CVE-2018-1000168
A vulnerability in nghttp2 could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on a targeted system.
The vulnerability is due to improper bounds checking by the affected software. If an alternative services (ALTSVC) frame is too large, the pointer field that points to the ALTSVC frame payload is left NULL. An attacker could exploit this vulnerability by sending a large ALTSVC frame to the targeted system. A successful exploit could trigger a NULL pointer dereference condition and cause the affected software to stop responding, resulting in a DoS condition on the affected system.
nghttp2.org has confirmed the vulnerability and released software updates.
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To exploit this vulnerability, an attacker must send a large ALTSVC frame to the targeted system, making exploitation more difficult in environments that restrict network access from untrusted sources.
This vulnerability affects client and server systems running an affected version of nghttp2 if the reception of ALTSVC frames is enabled. By default, receiving an ALTSVC frame is disabled.
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Administrators are advised to apply the appropriate updates.
Administrators are advised to allow only trusted users to have network access.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.
Administrators are advised to monitor affected systems.
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nghttp2.org has released a security advisory at the following link: CVE-2018-1000168
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nghttp2.org has released software updates at the following link: nghttp2 version 1.31.1
Duncan is a technology professional with over 20 years experience of working in various IT roles. He has a interest in cyber security, and has a wide range of other skills in radio, electronics and telecommunications.