Summary
A vulnerability in the sysadmin virtual machine (VM) on Cisco ASR 9000 Series Aggregation Services Routers running Cisco IOS XR 64-bit Software could allow an unauthenticated, remote attacker to access internal applications running on the sysadmin VM.
The vulnerability is due to incorrect isolation of the secondary management interface from internal sysadmin applications. An attacker could exploit this vulnerability by connecting to one of the listening internal applications. A successful exploit could result in unstable conditions, including both a denial of service and remote unauthenticated access to the device.
Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability.
This advisory is available at the following link: Cisco IOS XR 64-Bit Software for Cisco ASR 9000 Series Aggregation Services Routers Network Isolation Vulnerability
Affected Products
Vulnerable Products
This vulnerability affects Cisco ASR 9000 Series Aggregation Services Routers that are running an affected version of Cisco IOS XR 64-bit Software and have the secondary management interface (physically MGT LAN 1 on the route switch processor (RSP)) connected and configured. To determine if the secondary management interface is connected, log in to the sysadmin virtual machine and use the show interface command. If the secondary management interface is configured and connected, the device is vulnerable as shown in the following example (in dual route switch processor/route processor (RSP/RP) systems, check both active and standby RSP/RP):
Code:sysadmin-vm:0_RSP1:eXR# show interface Tue Mar 19 19:32:00.839 UTC MgmtEth0/RSP1/0/0 Link encap: Ethernet HWaddr 08:96:ad:22:7a:31 inet addr: 192.168.0.1 UP RUNNING BROADCAST MULTICAST MTU:1500 Metric:1 RX packets: 14093 errors:0 dropped:1 overruns:0 frame:0 TX packets: 49 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes: 867463 TX bytes: 6889 sysadmin-vm:0_RSP1:eXR#
For more information about which Cisco IOS XR Software releases are vulnerable, see the Fixed Software section of this advisory.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.
Cisco has confirmed that this vulnerability does not affect Cisco IOS-XR 64 bit Software running on platforms other than the ASR9000 Series Aggregation Services Routers.
Workarounds
Customers can perform the following workaround, which is equivalent to upgrading to a fixed software release. Although the reload of the sysadmin VM is hitless, Cisco recommends performing this change during a maintenance window:
Step 1: Access the sysadmin VM:
Code:RP/0/RSP1/CPU0:eXR#admin Tue Mar 12 22:46:37.110 UTC root connected from 127.0.0.1 using console on host
Step 2: Run bash and edit the calvados_bootstrap.cfg file:
Code:sysadmin-vm:0_RSP1:eXR# run bash Tue Mar 12 22:46:44.224 UTC bash-4.3# vi /etc/init.d/calvados_bootstrap.cfg
Step 3: Edit the file by changing:To:
Code:#CTRL_VRF=0 #MGMT_VRF=2
Code:CTRL_VRF=0 MGMT_VRF=2
Exit the file and save. In dual RSP/RP systems, the edit must be performed on both active and standby RSP/RPs.
Step 4: Reload the sysadmin VM (repeat for both in dual systems):
Code:sysadmin-vm:0_RSP1:eXR# reload admin location 0/RSP1 Tue Mar 12 22:49:28.589 UTC Reload node ? [no,yes] yes result Admin VM graceful reload request on 0/RSP1 succeeded. sysadmin-vm:0_RSP1:eXR# RP/0/RSP1/CPU0:Mar 12 22:49:34.059 UTC: rmf_svr[402]: %PKT_INFRA-FM-3-FAULT_MAJOR : ALARM_MAJOR :RP-RED-LOST-ADMINNR :DECLARE :0/RSP1/CPU0: Confd is down RP/0/RSP1/CPU0:eXR#
Wait till the admin VM returns:
Code:RP/0/RSP1/CPU0:eXR#0/RSP1/ADMIN0:Mar 12 22:59:30.220 UTC: envmon[3680]: %PKT_INFRA-FM-3-FAULT_MAJOR : ALARM_MAJOR :Power Module redundancy lost :DECLARE :0: RP/0/RSP1/CPU0:Mar 12 22:59:33.708 UTC: rmf_svr[402]: %PKT_INFRA-FM-3-FAULT_MAJOR : ALARM_MAJOR :RP-RED-LOST-ADMINNR :CLEAR :0/RSP1/CPU0:
Fixed Software
Cisco has released free software updates that address the vulnerability described in this advisory. Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license:
End User License Agreement
Additionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.
When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories and Alerts page, to determine exposure and a complete upgrade solution.
In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
Customers Without Service Contracts
Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC:
Cisco Worldwide Support Contacts
Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.
Fixed Releases
This vulnerability has been fixed in Cisco IOS XR 64-bit Software Release 6.5.3 and 7.0.1, which will edit the calvados_boostrap.cfg file and reload the device.
Cisco will not publish a software maintenance upgrade (SMU) for this vulnerability due to the effectiveness of the workaround.
Exploitation and Public Announcements
The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
Source
This vulnerability was found during internal security testing.
URL
Cisco IOS XR 64-Bit Software for Cisco ASR 9000 Series Aggregation Services Routers Network Isolation Vulnerability
Source: Cisco IOS XR 64-Bit Software for Cisco ASR 9000 Series Aggregation Services Routers Network Isolation Vulnerability
See also: Cisco warns over critical router flaw | ZDNet