Multiple DoS vulnerabilities in SSL VPN interface in Cisco Adaptive Security Appliance and Firepower Threat Defense
| Risk | Medium |
| Patch available | YES |
| Number of vulnerabilities | 3 |
| CVE-ID | CVE-2021-1573 CVE-2021-34704 CVE-2021-40118 |
| CWE-ID | CWE-121 CWE-20 CWE-787 |
| Exploitation vector | Network |
| Public exploit | N/A |
| Vulnerable software Subscribe |
Cisco Adaptive Security Appliance (ASA) Hardware solutions / Security hardware applicances Cisco Firepower Threat Defense (FTD) Hardware solutions / Security hardware applicances ASA 5500-X Series Firewalls Other software / Other software solutions |
| Vendor | Cisco Systems, Inc |
Security Bulletin
This security bulletin contains information about 3 vulnerabilities.
1) Stack-based buffer overflow
EUVDB-ID: #VU57755
Risk: Medium
CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]
CVE-ID: CVE-2021-1573
CWE-ID:
CWE-121 - Stack-based buffer overflow
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a boundary error when processing HTTP requests. A remote unauthenticated attacker can send a specially crafted HTTP request to exposed SSL VPN web interface, trigger stack-based buffer overflow and perform a denial of service (DoS) attack.
Install updates from vendor's website.
Vulnerable software versionsCisco Adaptive Security Appliance (ASA): 9.7 - 9.16
ASA 5500-X Series Firewalls: All versions
Cisco Firepower Threat Defense (FTD): 6.2.2 - 7.0.0
External linkshttp://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asafdt-webvpn-dos-KSqJAKPA
http://bst.cloudapps.cisco.com/bugsearch/bug/CSCvy36910
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
2) Input validation error
EUVDB-ID: #VU57756
Risk: Medium
CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]
CVE-ID: CVE-2021-34704
CWE-ID:
CWE-20 - Improper input validation
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to insufficient validation of user-supplied input when processing HTTP requests sent to the SSL VPN interface. A remote attacker can send a specially crafted config-request HTTP request and perform a denial of service (DoS) attack.
MitigationInstall updates from vendor's website.
Vulnerable software versionsCisco Adaptive Security Appliance (ASA): 9.15.1.7 - 9.16.1.28
ASA 5500-X Series Firewalls: All versions
Cisco Firepower Threat Defense (FTD): 6.7.0 - 7.0.0
External linkshttp://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asafdt-webvpn-dos-KSqJAKPA
http://bst.cloudapps.cisco.com/bugsearch/bug/CSCvy58278
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
3) Out-of-bounds write
EUVDB-ID: #VU57757
Risk: Medium
CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]
CVE-ID: CVE-2021-40118
CWE-ID:
CWE-787 - Out-of-bounds write
Exploit availability: No
Description The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a boundary error when processing HTTP requests in the SSL VPN interface. A remote attacker can create a specially crafted HTTP reuqst, trigger out-of-bounds write and perform a denial of service (DoS) attack.
Install updates from vendor's website.
Vulnerable software versionsCisco Adaptive Security Appliance (ASA): 9.7 - 9.16.2
Cisco Firepower Threat Defense (FTD): 6.2.2 - 7.0.0
ASA 5500-X Series Firewalls: All versions
External linkshttp://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asafdt-webvpn-dos-KSqJAKPA
http://bst.cloudapps.cisco.com/bugsearch/bug/CSCvy89144
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
