FreeBSD : nghttp2 -- Denial of service due to NULL pointer dereference (1fccb25e-8451-438c-a2b9-6a021e4d7a31)

high Nessus Plugin ID 109050

Language:

New! Plugin Severity Now Using CVSS v3

The calculated severity for Plugins has been updated to use CVSS v3 by default. Plugins that do not have a CVSS v3 score will fall back to CVSS v2 for calculating severity. Severity display preferences can be toggled in the settings dropdown.

Synopsis

The remote FreeBSD host is missing one or more security-related updates.

Description

nghttp2 blog :

If ALTSVC frame is received by libnghttp2 and it is larger than it can accept, the pointer field which points to ALTSVC frame payload is left NULL. Later libnghttp2 attempts to access another field through the pointer, and gets segmentation fault.

ALTSVC frame is defined by RFC 7838.

The largest frame size libnghttp2 accept is by default 16384 bytes.

Receiving ALTSVC frame is disabled by default. Application has to enable it explicitly by calling nghttp2_option_set_builtin_recv_extension_type(opt, NGHTTP2_ALTSVC).

Transmission of ALTSVC is always enabled, and it does not cause this vulnerability.

ALTSVC frame is expected to be sent by server, and received by client as defined in RFC 7838.

Client and server are both affected by this vulnerability if the reception of ALTSVC frame is enabled. As written earlier, it is useless to enable reception of ALTSVC frame on server side. So, server is generally safe unless application accidentally enabled the reception of ALTSVC frame.

Solution

Update the affected packages.

See Also

https://nghttp2.org/blog/2018/04/12/nghttp2-v1-31-1/

http://www.nessus.org/u?c63c4178

Plugin Details

Severity: High

ID: 109050

File Name: freebsd_pkg_1fccb25e8451438ca2b96a021e4d7a31.nasl

Version: 1.4

Type: local

Published: 4/16/2018

Updated: 11/10/2018

Dependencies: ssh_get_info.nasl

Risk Information

VPR

Risk Factor: Low

Score: 3.6

CVSS v2

Risk Factor: Medium

Base Score: 5

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P

CVSS v3

Risk Factor: High

Base Score: 7.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Vulnerability Information

CPE: cpe:2.3:o:freebsd:freebsd:*:*:*:*:*:*:*:*, p-cpe:2.3:a:freebsd:freebsd:nghttp2:*:*:*:*:*:*:*, p-cpe:2.3:a:freebsd:freebsd:libnghttp2:*:*:*:*:*:*:*

Required KB Items: Host/local_checks_enabled, Host/FreeBSD/release, Host/FreeBSD/pkg_info

Patch Publication Date: 4/13/2018

Vulnerability Publication Date: 4/4/2018

Reference Information

CVE: CVE-2018-1000168