Cisco IOS SIP消息拒绝服务漏洞

BUGTRAQ ID: 36499
CVE ID: CVE-2009-2870

Cisco IOS是思科网络设备所使用的互联网操作系统。

如果设备运行的Cisco IOS镜像中包含有Cisco Unified Border Element功能，则Cisco IOS软件的SIP实现中存在拒绝服务漏洞。处理一系列特制的SIP消息会导致设备重载。

Cisco IOS 12.4
Cisco IOS 12.3
临时解决方法：

• 禁用SIP监听端口

  sip-ua
  no transport udp
  no transport tcp
  no transport tcp tls

• 部署以下控制面整型（CoPP）

  !-- The 192.168.1.0/24 network and the 172.16.1.1 host are trusted.
  !-- Everything else is not trusted. The following access list is used
  !-- to determine what traffic needs to be dropped by a control plane
  !-- policy (the CoPP feature.) If the access list matches (permit)
  !-- then traffic will be dropped and if the access list does not
  !-- match (deny) then traffic will be processed by the router.

  access-list 100 deny udp 192.168.1.0 0.0.0.255 any eq 5060
  access-list 100 deny tcp 192.168.1.0 0.0.0.255 any eq 5060
  access-list 100 deny tcp 192.168.1.0 0.0.0.255 any eq 5061
  access-list 100 deny udp host 172.16.1.1 any eq 5060
  access-list 100 deny tcp host 172.16.1.1 any eq 5060
  access-list 100 deny tcp host 172.16.1.1 any eq 5061
  access-list 100 permit udp any any eq 5060
  access-list 100 permit tcp any any eq 5060
  access-list 100 permit tcp any any eq 5061

  !-- Permit (Police or Drop)/Deny (Allow) all other Layer3 and Layer4
  !-- traffic in accordance with existing security policies and
  !-- configurations for traffic that is authorized to be sent
  !-- to infrastructure devices.
  !-- Create a Class-Map for traffic to be policed by
  !-- the CoPP feature.

  class-map match-all drop-sip-class
  match access-group 100

  !-- Create a Policy-Map that will be applied to the
  !-- Control-Plane of the device.

  policy-map drop-sip-traffic
  class drop-sip-class
  drop

  !-- Apply the Policy-Map to the Control-Plane of the
  !-- device.

  control-plane
  service-policy input drop-sip-traffic

厂商补丁：

Cisco

Cisco已经为此发布了一个安全公告（cisco-sa-20090923-sip）以及相应补丁:
cisco-sa-20090923-sip：Cisco IOS Software Session Initiation Protocol Denial of Service Vulnerability
链接：http://www.cisco.com/warp/public/707/cisco-sa-20090923-sip.shtml