A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to conduct directory traversal attacks and read sensitive files on a targeted system. The vulnerability is due to a lack of proper input validation of URLs in HTTP requests processed by an affected device. An attacker could exploit this vulnerability by sending a crafted HTTP request containing directory traversal character sequences to an affected device. A successful exploit could allow the attacker to view arbitrary files within the web services file system on the targeted device. As an example, this could allow an attacker to impersonate another VPN user and establish a Clientless SSL VPN or AnyConnect VPN session to the device as that user. The web services file system is enabled when the affected device is configured with either WebVPN or AnyConnect features. This vulnerability cannot be used to obtain access to ASA or FTD system files, underlying operating system (OS) files, or VPN user login credentials. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. Note: Cisco has become aware of the availability of public exploit code and active exploitation of the vulnerability that is described in this advisory. Cisco encourages customers with affected products to upgrade to a fixed release as soon as possible. This advisory is available at the following link:https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ro-path-KJuQhB86
A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to conduct directory traversal attacks and read sensitive files on a targeted system.
The vulnerability is due to a lack of proper input validation of URLs in HTTP requests processed by an affected device. An attacker could exploit this vulnerability by sending a crafted HTTP request containing directory traversal character sequences to an affected device. A successful exploit could allow the attacker to view arbitrary files within the web services file system on the targeted device. As an example, this could allow an attacker to impersonate another VPN user and establish a Clientless SSL VPN or AnyConnect VPN session to the device as that user.
The web services file system is enabled when the affected device is configured with either WebVPN or AnyConnect features. This vulnerability cannot be used to obtain access to ASA or FTD system files, underlying operating system (OS) files, or VPN user login credentials.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
Note: Cisco has become aware of the availability of public exploit code and active exploitation of the vulnerability that is described in this advisory. Cisco encourages customers with affected products to upgrade to a fixed release as soon as possible.
This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ro-path-KJuQhB86
This vulnerability affects Cisco products if they are running a vulnerable release of Cisco ASA Software or Cisco FTD Software with a vulnerable AnyConnect or WebVPN configuration.
In the following table, the left column lists the Cisco ASA features that are vulnerable. The right column indicates the basic configuration for the feature from the show running-config CLI command. If the device is configured for one of these features, it is vulnerable.
| Cisco ASA Feature | Vulnerable Configuration |
|---|---|
| AnyConnect IKEv2 Remote Access (with client services) |
crypto ikev2 enable |
| AnyConnect SSL VPN |
webvpn |
| Clientless SSL VPN |
webvpn |
In the following table, the left column lists the Cisco FTD features that are vulnerable. The right column indicates the basic configuration for the feature from the show running-config CLI command. If the device is configured for one of these features, it is vulnerable.
On devices running Cisco FTD Software, the show running-config command is available from Diagnostic CLI mode only. To enter Diagnostic CLI mode, use the system support diagnostic-cli command in the regular Firepower Threat Defense CLI.
| Cisco FTD Feature | Vulnerable Configuration |
|---|---|
| AnyConnect IKEv2 Remote Access (with client services)1,2 |
crypto ikev2 enable |
| AnyConnect SSL VPN1,2 |
webvpn |
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 Firepower Management Center (FMC) Software.
The attacker can view files within the web services file system only. The web services file system is enabled for the WebVPN and AnyConnect features outlined in the Vulnerable Products section of this advisory; therefore, this vulnerability does not apply to the ASA and FTD system files or underlying operating system (OS) files. The web services files that the attacker can view may have information such as WebVPN configuration, bookmarks, web cookies, partial web content, and HTTP URLs.
There are no workarounds that address this vulnerability.
To help detect and/or block attempts to exploit the vulnerability that is described in this advisory, customers who use the SSL Decryption feature for affected traffic on Cisco Firepower sensors can enable Snort rules 54598 through 54601, from SRU number 2020-07-22-001, by using the Cisco Firepower Management Center.
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:
https://www.cisco.com/c/en/us/products/end-user-license-agreement.html
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 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 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: https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html
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.
In the following table(s), the left column lists Cisco software releases. The right column indicates whether a release is affected by the vulnerability described in this advisory and the first release that includes the fix for this vulnerability.
Cisco ASA Software
| Cisco ASA Software Release | First Fixed Release for This Vulnerability |
|---|---|
| Earlier than 9.61 | Migrate to a fixed release. |
| 9.6 | 9.6.4.42 |
| 9.71 | Migrate to a fixed release. |
| 9.8 | 9.8.4.20 |
| 9.9 | 9.9.2.74 |
| 9.10 | 9.10.1.42 |
| 9.12 | 9.12.3.12 |
| 9.13 | 9.13.1.10 |
| 9.14 | 9.14.1.10 |
Cisco FTD Software
| Cisco FTD Software Release | First Fixed Release for This Vulnerability |
|---|---|
| Earlier than 6.2.2 | Not vulnerable. |
| 6.2.2 | Migrate to a fixed release. |
| 6.2.3 | 6.2.3.16 |
| 6.3.0 | Migrate to 6.4.0.9 + Hot Fix or to 6.6.0.1 or 6.3.0.5 + Hot Fix1 or 6.3.0.6 (Fall 2020) |
| 6.4.0 | 6.4.0.9 + Hot Fix1 or 6.4.0.10 (Fall 2020) |
| 6.5.0 | Migrate to 6.6.0.1 or 6.5.0.4 + Hot Fix1 or 6.5.0.5 (Fall 2020) |
| 6.6.0 | 6.6.0.1 |
Cisco FTD Software Hot Fix Details
| Cisco FTD Software Release | Hot Fix File Names |
|---|---|
| 6.3.0.5 | Cisco_FTD_Hotfix_AV-6.3.0.6-3.sh.REL.tar Cisco_FTD_SSP_Hotfix_AV-6.3.0.6-3.sh.REL.tar Cisco_FTD_SSP_FP2K_Hotfix_AV-6.3.0.6-3.sh.REL.tar |
| 6.4.0.9 | Cisco_FTD_Hotfix_BM-6.4.0.10-2.sh.REL.tar Cisco_FTD_SSP_FP1K_Hotfix_BM-6.4.0.10-2.sh.REL.tar Cisco_FTD_SSP_FP2K_Hotfix_BM-6.4.0.10-2.sh.REL.tar Cisco_FTD_SSP_Hotfix_BM-6.4.0.10-2.sh.REL.tar |
| 6.5.0.4 | Cisco_FTD_Hotfix_O-6.5.0.5-3.sh.REL.tar Cisco_FTD_SSP_FP2K_Hotfix_O-6.5.0.5-3.sh.REL.tar Cisco_FTD_SSP_FP1K_Hotfix_O-6.5.0.5-3.sh.REL.tar Cisco_FTD_SSP_Hotfix_O-6.5.0.5-3.sh.REL.tar |
To upgrade to a fixed release of Cisco FTD Software, customers can do one of the following:
The Cisco Product Security Incident Response Team (PSIRT) is aware of the existence of public exploit code and active exploitation of the vulnerability that is described in this advisory.
Cisco would like to thank Mikhail Klyuchnikov of Positive Technologies and Abdulrahman Nour and Ahmed Aboul-Ela of RedForce for independently reporting this vulnerability.
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.
| Version | Description | Section | Status | Date |
|---|---|---|---|---|
| 1.5 | Clarified that VPN user login credentials are not exposed; updated availability of fixed software. | Summary, Fixed Software | Final | 2020-AUG-27 |
| 1.4 | Added more detail on potential impact. | Summary | Final | 2020-JUL-28 |
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