Cisco Adaptive Security Appliance (ASA) Software is affected by the following vulnerabilities: Cisco ASA ASDM Privilege Escalation Vulnerability Cisco ASA SSL VPN Privilege Escalation Vulnerability Cisco ASA SSL VPN Authentication Bypass Vulnerability Cisco ASA SIP Denial of Service Vulnerability These vulnerabilities are independent of one another; a release that is affected by one of the vulnerabilities may not be affected by the others. Successful exploitation of the Cisco ASA ASDM Privilege Escalation Vulnerability and the Cisco ASA SSL VPN Privilege Escalation Vulnerability may allow an attacker or an unprivileged user to elevate privileges and gain administrative access to the affected system. Successful exploitation of the Cisco ASA SSL VPN Authentication Bypass Vulnerability may allow an attacker to obtain unauthorized access to the internal network via SSL VPN. Successful exploitation of the Cisco ASA SIP Denial of Service Vulnerability may cause the exhaustion of available memory. This may cause system instability and in some cases lead to a reload of the affected system, creating a denial of service (DoS) condition. Cisco has released software updates that address these vulnerabilities. Workarounds that mitigate these vulnerabilities are available for some of the vulnerabilities. This advisory is available at the following link: http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20140409-asa Note: This security advisory does not provide information about the OpenSSL TLS Heartbeat Read Overrun Vulnerability identified by CVE-2014-0160 (also known as Heartbleed). For additional information regarding Cisco products affected by this vulnerability, refer to the Cisco Security Advisory at the following link: http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20140409-heartbleed
Cisco ASA Software is affected by this vulnerability if Cisco Adaptive Security Device Manager (ASDM) access is enabled and there is at least one user with privilege level 0 in the Cisco ASA local user database.
To verify whether Cisco ASDM access is configured, use the show running-config http command and verify that the HTTP server is enabled. The following example shows a Cisco ASA with the Cisco ASDM access enabled:
asa# show running-config http http server enable
To verify whether any user in the Cisco ASA local user database has been assigned privilege level 0, use the show running-config username | include privilege 0 command and verify that the command returns output. The following example shows a Cisco ASA Software configured with the user cisco1 with privilege level 0 assigned.
Note: Privilege level 0 is not assigned by default to any user.asa# show running-config username | include privilege 0 username cisco1 password jmINXNH6p1BxUppp encrypted privilege 0
Cisco ASA SSL VPN Privilege Escalation Vulnerability
Cisco ASA Software is affected by this vulnerability if the Cisco ASA Clientless or AnyConnect SSL VPN feature is enabled.
To determine whether the SSL VPN is enabled use the show running-config webvpn command.
The following example shows Cisco ASA Software with the SSL VPN feature enabled on the outside interface:
Vulmon
ciscoasa# show running-config webvpn
webvpn
enable outside
Note: Cisco ASA SSL VPN is disabled by default.
ciscoasa# show running-config webvpn
webvpn
enable outside
To determine whether the authorization-required command is configured under the general attribute of a tunnel group, use the show running-config tunnel-group ciscoasa# show running-config tunnel-group Clientless
tunnel-group Clientless type remote-access
tunnel-group Clientless general-attributes
authentication-server-group AAA_RADIUS
authorization-server-group AAA_RADIUS
[...]
tunnel-group Clientless webvpn-attributes
authentication aaa
[...]
Note: Cisco ASA SSL VPN is disabled by default. Devices running Cisco ASA Software releases prior to 8.4 are not affected by this vulnerability when both the following conditions are met:
ciscoasa# show service-policy | include sip
Inspect: sip , packet 67, drop 0, reset-drop 0
Note: SIP inspection functionality is enabled by default. Customers who use the Cisco ASDM to manage devices can locate the software version in the table that is displayed in the login window or the upper-left corner of the Cisco ASDM window.ciscoasa#show version | include Version
Cisco Adaptive Security Appliance Software Version 8.4(1)
Device Manager Version 6.4(1)
A vulnerability in the SSL VPN code could allow an unauthenticated, remote attacker to access the SSL VPN portal web page.
The vulnerability is due to improper handling of authentication cookies when the Cisco ASA SSL VPN feature is enabled. An attacker could exploit this vulnerability by manually modifying the HTTP POST body with a forged cookie value or entering a crafted URL. An exploit could allow the attacker to gain unauthenticated access to the SSL VPN Portal page. Depending on the SSL VPN configuration, the attacker may also start a VPN tunnel by using Cisco AnyConnect.A vulnerability in the SIP inspection engine code could allow an unauthenticated, remote attacker to exhaust available memory, which may cause instability or a reload of the affected system.
The vulnerability is due to improper handling of SIP packets inspected by the Cisco ASA SIP inspection engine. An attacker could exploit this vulnerability by sending crafted SIP packets through the affected system. An exploit could allow the attacker to cause the exhaustion of available memory. This may cause system instability and in some cases lead to a reload of the affected system, creating a denial of service condition.Cisco ASA ASDM Privilege Escalation Vulnerability
To workaround this vulnerability, administrators can assign privilege level 1 instead of privilege level 0 to users. The privilege assignment can be overridden by reapplying the command with the new privilege level.
The following example shows how to change the privilege level for the user cisco1 in the Cisco ASA local user database from level 0 to level 1.
asa(config)# username cisco1 passwordprivilege 1
Note: This command will override the password value as well. Depending on the specific configuration, assigning privilege level 1 instead of privilege level 0 may allow authorization to commands that user with privilege level 0 would normally not have access to. Customers should carefully evaluate of the workaround is acceptable in their environment.
The Cisco ASA Dynamic Access Policy (DAP) feature can be used as a workaround to terminate any connection that does not have a username by creating a DAP record that contains the terminate action, and is selected based on the following advanced selection rule: aaa.cisco.username == ""
This workaround applies to all vulnerable releases.
Note: This workaround could break deployments that allow nameless sessions to be created. This will occur when certificate-only authentication is used and the Cisco ASA is not configured to extract a username from the user’s certificate.ciscoasa(config)# policy-map global_policy
ciscoasa(config-pmap)# class inspection_default
ciscoasa(config-pmap-c)# no inspect sip
When considering software upgrades, customers are advised to consult the Cisco Security Advisories, Responses, and Notices 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.
In February
2014, Cisco announced details of an industry-wide issue with memory
components manufactured by a single supplier between 2005 and 2010.
Although the majority of Cisco products that use these components are
experiencing field failure rates below expected levels, a device reload
or power cycle could expose component failures. While there are no known
security implications associated with this issue, a subset of the
affected products may experience a memory component failure during the
software upgrade process. Cisco recommends customers review the related
information and product-specific field notices at www.cisco.com/go/memory
before making upgrade decisions. Each Field Notice indicates whether
the product could experience the memory component failure during a
software upgrade.
| 7.01 |
7.11 |
7.2 |
8.01 |
8.11 |
8.2 |
8.3 |
8.4 |
8.5 |
8.6 |
8.7 |
9.0 |
9.1 |
9.2 |
|
|
Cisco ASA ASDM Privilege Escalation Vulnerability - CSCuj33496 |
Not Affected |
Not Affected |
Not Affected |
Not Affected |
Not Affected |
8.2(5.47) |
Not Affected |
8.4(7.5) |
Not Affected |
Not Affected |
8.7(1.11) |
9.0(3.10) |
9.1(3.4) |
Not Affected |
|
Cisco ASA SSL VPN Privilege Escalation Vulnerability - CSCul70099 |
Not Affected |
Not Affected |
Not Affected |
Migrate to 8.2.x or later |
Migrate to 8.2.x or later |
8.2(5.48) |
8.3(2.40) |
8.4(7.9) |
Not Affected |
8.6(1.13) |
Not Affected |
9.0(4.1) |
9.1(4.3) |
Not Affected |
|
Cisco ASA SSL VPN Authentication Bypass Vulnerability
- CSCua85555
|
Not Affected |
Not Affected |
Not Affected |
Not Affected |
Not Affected |
8.2(5.47) |
8.3(2.40) |
8.4(7.3) |
Not Affected |
8.6(1.13) |
Not Affected |
9.0(3.8) |
9.1(3.2) |
Not Affected |
| Cisco ASA SIP Denial of Service Vulnerability - CSCuh44052 |
Not Affected |
Not Affected |
Not Affected |
Not Affected |
Not Affected |
8.2(5.48) |
Not Affected |
8.4(6.5) |
Not Affected |
Not Affected |
Not Affected |
9.0(3.1) |
9.1(2.5) |
Not Affected |
| Recommended release that fixes all the vulnerabilities in this security advisory |
Not Affected |
Not Affected |
Not Affected |
Migrate to 8.2.x or later |
Migrate to 8.2.x or later |
8.2(5.48) or later |
8.3(2.40) or later |
8.4(7.15) or later |
Not Affected |
8.6(1.13) or later |
8.7(1.11) or later |
9.0(4.1) or later |
9.1(4.5) or later |
Not Affected |
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.
The Cisco ASA ASDM Privilege Escalation Vulnerability and Cisco ASA SIP Denial of Service Vulnerability were discovered during the resolution of support cases.
The Cisco ASA SSL VPN Privilege Escalation Vulnerability was reported to Cisco by Jonathan Claudius from Trustwave
SpiderLabs and Laura Guay from Dell SecureWorks.
The Cisco ASA SSL VPN Authentication Bypass Vulnerability was reported to Cisco by Daniel Cannon and Simon Whitehouse from IRM PLC.
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.
| Revision 1.1 | 2014-April-18 | Updated information about the SSL VPN vulnerabilities. |
| Revision 1.0 | 2014-April-09 | Initial public release. |
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