CVE-2020-11091— Weaveworks Weave Net 安全漏洞

Weave Net clusters susceptible to MitM attacks via IPv6 rogue router advertisements

In Weave Net before version 2.6.3, an attacker able to run a process as root in a container is able to respond to DNS requests from the host and thereby insert themselves as a fake service. In a cluster with an IPv4 internal network, if IPv6 is not totally disabled on the host (via ipv6.disable=1 on the kernel cmdline), it will be either unconfigured or configured on some interfaces, but it's pretty likely that ipv6 forwarding is disabled, ie /proc/sys/net/ipv6/conf//forwarding == 0. Also by default, /proc/sys/net/ipv6/conf//accept_ra == 1. The combination of these 2 sysctls means that the host accepts router advertisements and configure the IPv6 stack using them. By sending rogue router advertisements, an attacker can reconfigure the host to redirect part or all of the IPv6 traffic of the host to the attacker controlled container. Even if there was no IPv6 traffic before, if the DNS returns A (IPv4) and AAAA (IPv6) records, many HTTP libraries will try to connect via IPv6 first then fallback to IPv4, giving an opportunity to the attacker to respond. If by chance you also have on the host a vulnerability like last year's RCE in apt (CVE-2019-3462), you can now escalate to the host. Weave Net version 2.6.3 disables the accept_ra option on the veth devices that it creates.

CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:N/I:H/A:N

不恰当地信任反向DNS

Weaveworks Weave Net 安全漏洞

Weaveworks Weave Net是英国Weaveworks公司的一款云原生网络工具包。 Weaveworks Weave Net 2.6.3之前版本中存在安全漏洞。目前尚无此漏洞的相关信息，请随时关注CNNVD或厂商公告。

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