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Cisco Security Advisory

Multiple Vulnerabilities in Cisco ASA 5500 Series Adaptive Security Appliances and Cisco Catalyst 6500 Series ASA Services Module

Critical
Advisory ID:
cisco-sa-20121010-asa
First Published:
2012 October 10 16:00 GMT
Version 1.0:
Final
Workarounds:
See below
CVE-2012-4643
CVE-2012-4659
CVE-2012-4660

More...

CWE-119
CVSS Score:
Base 9.0, Temporal 7.4Click Icon to Copy Verbose Score
AV:N/AC:M/Au:N/C:C/I:P/A:C/E:F/RL:OF/RC:C
CVE-2012-4643
CVE-2012-4659
CVE-2012-4660

More...

CWE-119

Summary

  • Cisco ASA 5500 Series Adaptive Security Appliances (ASA) and Cisco Catalyst 6500 Series ASA Services Module (ASASM) may be affected by the following vulnerabilities:
    • DHCP Memory Allocation Denial of Service Vulnerability
    • SSL VPN Authentication Denial of Service Vulnerability
    • SIP Inspection Media Update Denial of Service Vulnerability
    • DCERPC Inspection Buffer Overflow Vulnerability
    • Two DCERPC Inspection Denial Of Service Vulnerabilities

    These vulnerabilities are independent of each other; a release that is affected by one of the vulnerabilities may not be affected by the others.

    Successful exploitation of any of these vulnerabilities could allow an unauthenticated remote attacker to trigger a reload of the affected device. Exploitation of the DCERPC Inspection Buffer Overflow Vulnerability could additionally cause a stack overflow and possibly the execution of arbitrary commands.

    Cisco has released software updates that address these vulnerabilities. Workarounds are available for some of these vulnerabilities. This advisory is available at the following link:
    https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20121010-asa

    Note: The Cisco Firewall Services Module for Cisco Catalyst 6500 and Cisco 7600 Series (FWSM) may be affected by some of the vulnerabilities listed above.
    A separate Cisco Security Advisory has been published to disclose the vulnerabilities that affect the Cisco FWSM. This advisory is available at:
    https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20121010-fwsm

    The Cisco ASA 1000V Cloud Firewall and Cisco ASA-CX Context-Aware Security are not affected by any of these vulnerabilities.

Affected Products

  • Cisco ASA 5500 Series Adaptive Security Appliances and Cisco Catalyst 6500 Series ASA Services Module are affected by multiple vulnerabilities. Affected versions of Cisco ASA Software will vary depending on the specific vulnerability. Consult the "Software Versions and Fixes" section of this security advisory for more information about the affected versions.

    Cisco PIX Security Appliances may be affected by some of the vulnerabilities described in this security advisory. Cisco PIX has reached end of software maintenance. Cisco PIX Security Appliance customers are encouraged to migrate to Cisco ASA 5500 Series Adaptive Security Appliances. Consult the dedicated section for Cisco PIX Security Appliances in the "Vulnerable Products" section of this security advisory for more information about affected versions.

    Vulnerable Products

    For specific version information, refer to the "Software Versions and Fixes" section of this advisory.

    DHCP Memory Allocation Denial of Service Vulnerability

    This vulnerability is triggered when the Cisco ASA Software processes a DHCP request. DHCP relay and DHCP server features will trigger the DHCP request packet process. If either feature is enabled, the Cisco ASA Software may be vulnerable.

    To determine whether the DHCP server feature is enabled on Cisco ASA Software use the show dhcpd state command and verify that at least one interface is configured for DHCP server. The following example shows the Cisco ASA Software with DHCP server enabled on the inside interface 

    ciscoasa# show dhcpd state
Context  Configured as DHCP Server
Interface inside, Configured for DHCP SERVER

    To determine whether the DHCP relay feature is enabled on Cisco ASA Software use the show dhcprelay state command and verify that DHCP relay is active. The following example shows the Cisco ASA Software with DHCP relay enabled.

    ciscoasa# show dhcprelay state
    Context  Configured as DHCP Relay
    Interface outside, Configured for DHCP RELAY SERVER
    Interface inside, Configured for DHCP RELAY

    Note: By default, DHCP server is enabled on the inside interface of the Cisco ASA 5505 and on the management interface of all other Cisco ASA 5500 Series Adaptive Security Appliances. DHCP server is disabled by default on Cisco Catalyst 6500 Series ASA Services Module.

    DHCP relay feature is not enabled by default on any Cisco ASA 5500 Series Adaptive Security Appliances and Cisco Catalyst 6500 Series ASA Services Module platforms.




    SSL VPN Authentication Denial of Service Vulnerability

    This vulnerability may affect Cisco ASA Software configured for Clientless or AnyConnect SSL VPN. Cisco ASA Software configured as an IPsec VPN Server, IPsec/L2TP VPN Server or IKEv2 AnyConnect VPN server is not affected. Because this vulnerability is triggered when receiving a crafted authentication challenge-response, Cisco ASA Software is not affected when configured to use the AAA protocol that does not support the challenge option or with the challenge option disabled.

    To be affected, the Cisco ASA Software should have SSL VPN enabled and the tunnel group configured to authenticate to a remote AAA server using a AAA protocol that has the AAA challenge option enabled.

    Currently the following AAA setup may be configured with the challenge option enabled and hence be considered vulnerable:

    1. Native RSA SecurID (also known as SDI) - This is vulnerable when the SecureID server requires a challenge response from the user.
    2. RADIUS and TACACS+ authentication challenge - These are vulnerable when the AAA server uses a token-based authentication system which is capable of sending challenge requests to authenticating users.
    3. Active Directory password management via RADIUS or LDAP. In these cases the Cisco ASA Software facilitates a user password change prior to authentication with Active Directory.
    Other AAA authentication methods supported by the Cisco ASA Software such as HTTP form-based or using NT LAN Manager (NTLM) and Kerberos authentication protocols are not affected by this vulnerability.

    To determine whether Cisco ASA Software has SSL VPN enabled use the show running-config webvpn command and verify that SSL VPN is enabled on at least one interface. The following example shows the Cisco ASA Software with SSL VPN enabled on the outside interface:

    ciscoasa# show running-config webvpn
webvpn
 enable outside

    To determine whether the Cisco ASA Software has the tunnel group configured for a remote AAA server, use the show running-config tunnel-group general-attributes command and verify that the authentication-server-group is set to authenticate to a remote AAA server. The following example shows the Cisco ASA Software with the tunnel group WebVPN configured to authenticate against a remote AAA server with tag labeled RSA.

    ciscoasa#show running-config tunnel-group WebVPN general-attributes
tunnel-group WebVPN general-attributes
 authentication-server-group RSA

    To determine which AAA protocol is in use for a given AAA server, use the show aaa-server . The AAA protocol in use is indicated under Server Group. The following example shows a AAA server with tag labeled RSA which is using RSA SecurID (SDI) as AAA protocol: 

    ciscoasa# show aaa-server RSA
    Server Group:    RSA
    Server Protocol: sdi

    Note: SSL VPN is not enabled by default. The default AAA setting for tunnel group is LOCAL which is not affected by this vulnerability.



    SIP Inspection Media Update Denial of Service Vulnerability

    The Cisco ASA Software may be affected by this vulnerability if Session Initiation Protocol (SIP) inspection is enabled.

    To determine whether SIP inspection is enabled use the show service-policy inspect sip command. The following example shows Cisco ASA Software with SIP inspection enabled: 

    ciscoasa# show service-policy | include sip
          Inspect: sip , packet 67, drop 0, reset-drop 0


    Note: SIP inspection functionality is enabled by default.



    DCERPC Inspection Buffer Overflow Vulnerability and DCERPC Inspection Denial Of Service Vulnerabilities

    Cisco ASA Software is affected by these vulnerabilities if DCERPC inspection is enabled.

    To determine whether the DCERPC inspection is enabled use the show service-policy | include dcerpc command. The following example shows the Cisco ASA Software with DCERPC inspection enabled: 

    ciscoasa# show  service-policy | include dcerpc
          Inspect: dcerpc, packet 0, drop 0, reset-drop 0

    Note: DCERPC inspection is not enabled by default.



    

    Determine the Running Software Version
    

    To determine whether a vulnerable version of Cisco ASA Software is running on an appliance, administrators can issue the show version
command. The following example shows a Cisco ASA 5500 Series Adaptive
Security Appliance that is running software version 8.4(1):
    

    

    ciscoasa#show version | include Version
    Cisco Adaptive Security Appliance Software Version 8.4(1) 
    Device Manager Version 6.4(1)
    

    Customers who use Cisco Adaptive Security Device Manager (ASDM) to
manage devices can locate the software version in the table that is
displayed in the login window or upper-left corner of the Cisco ASDM
window.
    

    

    Information about Cisco PIX Security Appliance Software
    
All versions of the Cisco PIX Security Appliance Software are affected by the DHCP Memory Allocation Denial of Service Vulnerability.
    

    
Cisco PIX Security Appliance Software is not affected by any other vulnerabilities described in this security advisory.
    

    
                                    Products Confirmed Not Vulnerable
                                    
                                  
    

    The Cisco ASA 1000V Cloud Firewall and Cisco ASA-CX Context-Aware Security are not affected by any of these vulnerabilities.
    

    
With the exception of the Cisco FWSM, no other Cisco products are currently known to be affected by these vulnerabilities.
    

    
    

    

    • 







                          Details
                          
                        




    

  • 

    
The following section provides additional information about each vulnerability.
    

    
DHCP Memory Allocation Denial of Service Vulnerability
    

    

    DHCP is a
protocol that supplies automatic configuration parameters such as an IP
address with a subnet mask, default gateway, DNS server, and WINS server
IP address to hosts. 
    

    The
Cisco ASA Software can act as a DHCP server or a DHCP client. When it operates
as a server, the Cisco ASA Software provides network configuration parameters
directly to DHCP clients.  
    

    A
vulnerability exists in the implementation of the Dynamic Host
Configuration Protocol (DHCP) Server functionality that
would allow an unauthenticated, remote attacker to trigger a reload of
the affected device. This vulnerability is due to a failure in
allocating memory for an internal DHCP data structure upon receiving
crafted DHCP packets. An attacker could exploit this vulnerability by
sending a sequence of crafted DHCP packets to the affected system 
    

    Note: This vulnerability may be triggered by both transit traffic and traffic directed to the affected device. This vulnerability affects both routed and transparent firewall modes in both single-context and multicontext modes. This vulnerability can be triggered only by
IPv4 traffic. 

    

    
This vulnerability is documented in Cisco bug ID, CSCtw84068 (registered customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2012-4643
    

    
SSL VPN Authentication Denial of Service Vulnerability
    

    
The Cisco ASA Software includes two types of SSL VPN, which is a technology for remote access to corporate resources:
    

      
    
    • Clientless SSL VPN provides access to Web applications, such as email, and
    corporate portals via Web browsers and Java components. It requires no
    client software.
    
      • 
    
    • The AnyConnect SSL VPN Client.
      • 

    

    
A vulnerability exists in the implementation of the
authentication, authorization and accounting (AAA) code for remote
the SSL VPN (Clientless and AnyConnect) feature that could allow an
unauthenticated, remote attacker to trigger a reload of the affected
system. This vulnerability is due to insufficient validation of  a crafted
authentication response when a AAA challenge-response is required to complete the
authentication process. An attacker could exploit this vulnerability by
trying to authenticate on an ASA configured for SSL VPN with a
crafted authentication challenge response.

    This
vulnerability affects a Cisco ASA Software configured for Clientless or AnyConnect SSL VPN. Cisco ASA Software configured as an IPsec VPN Server, IPSEC/L2TP VPN Server or IKEv2 AnyConnect server is not affected.
    
Note:
Only traffic destined to the affected device can be used to exploit
this vulnerability. This vulnerability affects only Cisco ASA Software configured in
routed and single context mode. This vulnerability can be triggered by
IPv4 traffic only.
    

    
This vulnerability is documented in Cisco bug ID, CSCtz04566 (registered customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2012-4659
    

    
SIP Inspection Media Update Denial of Service Vulnerability
    

    

    Session Initiation Protocol (SIP) as defined by the
Internet Engineering Task Force (IETF), enables call handling sessions,
particularly two-party audio conferences. SIP works with Session Description Protocol (SDP)
for call signaling. SDP specifies the ports for the media stream.
Cisco ASA Software supports dynamic allocation of ports for media stream via a dedicated SIP inspection engine.
    

    A vulnerability exists in the SIP inspection engine code of the Cisco ASA Software, that
may allow an unauthenticated, remote attacker to trigger a reload of
the affected device.  This vulnerability is due to improper processing
of SIP media update packets. An attacker could exploit this vulnerability by sending a crafted SIP packet through the affected system. The
packets that trigger this vulnerability must be part of an established
SIP inspection session that needs to be inspected by the affected system.
    

    
Note: Only transit traffic can be used to exploit this vulnerability.  This
vulnerability affects both routed and transparent firewall mode in both
single and multi-context mode. This vulnerability can be triggered by
IPv4 and IPv6 traffic. 

    

    
This vulnerability is documented in Cisco bug ID, CSCtr63728 (registered customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2012-4660
    

    
    DCERPC Inspection Buffer Overflow Vulnerability
    

    
DCERPC is a protocol that is widely used by Microsoft distributed client and server applications that allows software
clients to remotely execute programs on a server.
    

    
A vulnerability exists in the DCERPC inspection engine that would allow an
unauthenticated, remote attacker to cause a reload of the affected system or to overflow the stack and possibly execute arbitrary commands. The vulnerability is due to insufficient validation of DCERPC packets within a valid DCERPC session. An attacker could exploit this vulnerability by
sending a crafted DCERPC packet that needs to be inspected by the affected system.

    

    
Note: Only transit traffic can be used to exploit
this vulnerability. This vulnerability affects both routed and
transparent firewall mode in both single and multi-context mode. This
vulnerability can be triggered by IPv4 and IPv6 traffic.
    

    
This vulnerability is documented in Cisco bug ID, CSCtr21359 (registered customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2012-4661
    

    
DCERPC Inspection Denial Of Service Vulnerabilities
    

    
Two vulnerabilities exist in the DCERPC inspection engine that would allow an
unauthenticated, remote attacker to cause a reload of the affected system. The vulnerabilities are due to insufficient validation of DCERPC packets within a valid DCERPC session. An attacker could exploit this vulnerability by
sending a crafted DCERPC packet that needs to be inspected by the affected system.
    

    
Note: Only transit traffic can be used to exploit
these vulnerabilities. This vulnerabilities affects both routed and
transparent firewall mode in both single and multi-context mode. These vulnerabilities can be triggered by IPv4 and IPv6 traffic.
    

    
These vulnerabilities are documented in Cisco bug IDs, CSCtr21376 (registered customers only) and CSCtr21346 (registered customers only) and have been assigned Common Vulnerabilities and Exposures (CVE) IDs CVE-2012-4662 and  CVE-2012-4663
    

    
    

    

    • 







                          Workarounds
                          
                        




    

  • 

    The following section contains information about a workaround, if available, for each vulnerability described in this security advisory.
    

    DHCP Memory Allocation Denial of Service Vulnerability
    

    
    Besides disabling the DHCP server and DHCP relay features, there are no workarounds that mitigate this vulnerability. 
    

    
SSL VPN Authentication Denial of Service Vulnerability
    

    
    There are no workarounds that mitigate this vulnerability. 
    

    
SIP Inspection Media Update Denial of Service Vulnerability
    

    
    
Disabling SIP inspection will mitigate this vulnerability.

    
The following commands will disable the SIP inspection that is configured by default:
    

    

    ciscoasa(config)# policy-map global_policy
ciscoasa(config-pmap)# class inspection_default
ciscoasa(config-pmap-c)# no inspect sip
    

    

    

    
DCERPC Inspection Buffer Overflow Vulnerability and DCERPC Inspection Denial Of
Service Vulnerabilities
    

    Besides disabling the DCERPC inspection, there are no workarounds that mitigate these vulnerabilities. 
    

    
 
    

    

    

    • 







                          Fixed Software
                          
                        




    

  • 

    When considering software upgrades, customers are advised to consult the Cisco Security Advisories and Responses archive at http://www.cisco.com/go/psirt and review subsequent advisories 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. 
    

    
DHCP Memory Allocation Denial of Service Vulnerability
    

    

    
    
        
    
            Vulnerability
            Major Release
    
                		
            First Fixed Release
    
                		
        
    
        
    
            
    
                DHCP Memory Allocation Denial of Service Vulnerability - CSCtw84068
            
    
                		
            7.0
            7.2(5.8)
    
                		
        
    
        
    
            7.1
            7.2(5.8)
    
                		
        
    
        
    
            7.2
            7.2(5.8)
    
                		
        
    
        
    
            8.0
            8.0(5.28)
    
                		
        
    
        
    
            8.1
            8.1(2.56)
    
                		
        
    
        
    
            8.2
            8.2(5.27) 
        
    
        
    
            8.3
            8.3(2.31)
        
    
        
    
            8.4
            8.4(3.10)
        
    
        
    
            8.5
            8.5(1.9)
    
                		
        
    
        
    
            8.6
            8.6(1.5)
    
                		
        
    
        

    

    

    
SSL VPN Authentication Denial of Service Vulnerability
    

    

    
    
        
    
            Vulnerability
            Major Release
    
                		
            First Fixed Release
    
                		
        
    
        
    
            
    
            SSL VPN Authentication Denial of Service Vulnerability - CSCtz04566
            
    
                		
            7.0
            Not Affected
    
                		
        
    
        
    
            7.1
            Not Affected
    
                		
        
    
        
    
            7.2
            Not Affected
    
                		
        
    
        
    
            8.0
             Not Affected
    
                		
        
    
        
    
            8.1
             Not Affected
    
                		
        
    
        
    
            8.2
            8.2(5.30)
        
    
        
    
            8.3
            8.3(2.34)
    
                		
        
    
        
    
            8.4
            Not Affected 
        
    
        
    
            8.5
            Not Affected 
        
    
        
    
            8.6
            Not Affected
        
    
        

    

    
SIP Inspection Media Update Denial of Service Vulnerability
    

    

    
    
        
    
            Vulnerability
            Major Release
    
                		
            First Fixed Release
    
                		
        
    
        
    
            
    
            SIP Inspection Media Update Denial of Service Vulnerability - CSCtr63728
            
    
                		
            7.0
            Not Affected
    
                		
        
    
        
    
            7.1
            Not Affected
    
                		
        
    
        
    
            7.2
            Not Affected
    
                		
        
    
        
    
            8.0
            Not Affected 
    
                		
        
    
        
    
            8.1
            Not Affected
        
    
        
    
            8.2
            8.2(5.17)
        
    
        
    
            8.3
            8.3(2.28)
        
    
        
    
            8.4
            8.4(2.13)
        
    
        
    
            8.5
            8.5(1.4)
        
    
        
    
            8.6
            8.6(1.5)
    
                		
        
    
        

    

    
DCERPC Inspection Buffer Overflow Vulnerability
    

    

    
    
        
    
            Vulnerability
            Major Release
    
                		
            First Fixed Release
    
                		
        
    
        
    
            DCERPC Inspection Buffer Overflow Vulnerability -
            CSCtr21359
            
    
                		
            7.0
            Not Affected
    
                		
        
    
        
    
            7.1
            Not Affected
    
                		
        
    
        
    
            7.2
            Not Affected 
        
    
        
    
            8.0
            Not Affected 
        
    
        
    
            8.1
            Not Affected 
        
    
        
    
            8.2
            Not Affected 
        
    
        
    
            8.3
            8.3(2.34) 
        
    
        
    
            8.4
            8.4(4.4) 
        
    
        
    
            8.5
            8.5(1.13) 
        
    
        
    
            8.6
            8.6(1.3) 
        
    
        

    

    
DCERPC Inspection Denial Of Service Vulnerabilities
    

    

    
    
        
    
            Vulnerability
            Major Release
    
                		
            First Fixed Release
    
                		
        
    
        
    
            DCERPC Inspection Denial Of Service Vulnerabilities - CSCtr21376
            and CSCtr21346
    
                		
            7.0
            Not Affected
    
                		
        
    
        
    
            7.1
            Not Affected
    
                		
        
    
        
    
            7.2
            Not Affected 
        
    
        
    
            8.0
            Not Affected 
        
    
        
    
            8.1
            Not Affected 
        
    
        
    
            8.2
            Not Affected 
        
    
        
    
            8.3
            8.3(2.25) 
        
    
        
    
            8.4
            8.4(2.5) 
        
    
        
    
            8.5
            8.5(1.13) 
        
    
        
    
            8.6
            Not Affected 
        
    
        

    

    

    

    Recommended Releases
    

    The following table lists all recommended releases. These recommended
releases contain the fixes for all vulnerabilities in this advisory.
Cisco recommends upgrading to a release that is equal to or later than
these recommended releases.
    

    
    
        
    
            
            
    Major Release
    
                		
            
            
    Recommended Release
    
                		
        
    
        
    
            7.0 
            7.2(5.8) 
        
    
        
    
            7.1 
            7.2(5.8) 
        
    
        
    
            7.2 
            7.2(5.8) 
        
    
        
    
            8.0 
            8.0(5.28) 
        
    
        
    
            8.1 
            8.1(2.56) 
        
    
        
    
            8.2 
            8.2(5.33) 
        
    
        
    
            8.3 
            8.3(2.34) 
        
    
        
    
            8.4 
            8.4(4.5) 
        
    
        
    
            8.5 
            8.5(1.14) 
        
    
        
    
            8.6 
            8.6(1.5) 
        
    
        

    

    

    Software Download
    
Cisco ASA Software can be downloaded from the Software Center on Cisco.com by visiting http://www.cisco.com/cisco/software/navigator.html

    For Cisco ASA 5500 Series Adaptive Security Appliances, navigate to Products
> Security > Firewalls > Adaptive Security Appliances (ASA) > Cisco ASA
5500 Series Adaptive Security Appliances >  > Adaptive Security Appliance (ASA) Software. Please note that some of these versions are interim versions and they can be found by expanding the Interim tab on the download page.
    

    For Cisco Catalyst 6500 Series ASA Services Module, navigate to Products
> Cisco Interfaces and Modules > Cisco Services Modules >Cisco
Catalyst 6500 Series ASA Services Module > ASA Services Module
(ASASM) Software. Please note that some of these versions are interim versions and they can be found by expanding the Interim tab on the download page.
    

    • 






                          Exploitation and Public Announcements
                          
                        




    

  • 

    The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerabilities that are described in this advisory. 
    

    All the vulnerabilities described in this security advisory were found
during internal testing or discovered during the resolution of customer
support cases.
    

    • 










        Cisco Security Vulnerability Policy
        
      




    

  • 

    

    To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
    

    

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                        Revision History
                        
                      




    

  • 

    
	
		
    
			Revision 1.0
			2012-October-10
			Initial public release
		
    
	    

    
Show Less

    

    • 





















        Cisco Security Vulnerability Policy
        
      




    

  • 

    

    To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
    

    

    • 





Subscribe to Cisco Security Notifications








          
          Action Links for This Advisory
        








          
          Related to This Advisory