Cisco Adaptive Security Appliance Software WebVPN CRLF Injection (cisco-sa-asa-ftd-crlf-inj-BX9uRwSn)

medium Nessus Plugin ID 149526
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The remote device is missing a vendor-supplied security patch


According to its self-reported version, the Clientless SSL VPN (WebVPN) of Cisco Adaptive Security Appliance (ASA) Software is affected by an CRLF injection vulnerability due to improper input sanitization. An unauthenticated, remote attacker can exploit this by persuading a user of the interface to click a crafted link which could allow the attacker to conduct a CRLF injection attack, adding arbitrary HTTP headers in the responses of the system and redirecting the user to arbitrary websites.

Please see the included Cisco BID and Cisco Security Advisory for more information.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.


Upgrade to the relevant fixed version referenced in Cisco bug ID CSCvt18028

See Also

Plugin Details

Severity: Medium

ID: 149526

File Name: cisco-sa-asa-ftd-crlf-inj-BX9uRwSn-asa.nasl

Version: 1.6

Type: local

Family: CISCO

Published: 5/17/2021

Updated: 6/1/2021

Dependencies: ssh_get_info.nasl

Risk Information

CVSS Score Source: CVE-2020-3561


Risk Factor: Low

Score: 1.6


Risk Factor: Medium

Base Score: 4.3

Temporal Score: 3.2

Vector: AV:N/AC:M/Au:N/C:N/I:P/A:N

Temporal Vector: E:U/RL:OF/RC:C


Risk Factor: Medium

Base Score: 4.7

Temporal Score: 4.1

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N

Temporal Vector: E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:cisco:adaptive_security_appliance_software

Required KB Items: Host/Cisco/ASA

Exploit Ease: No known exploits are available

Patch Publication Date: 10/21/2020

Vulnerability Publication Date: 10/21/2020

Reference Information

CVE: CVE-2020-3561

IAVA: 2020-A-0488


CISCO-SA: cisco-sa-asa-ftd-crlf-inj-BX9uRwSn

CWE: 93