cbcvebase.
CVE-2020-3529
published 2020-10-21

CVE-2020-3529: A vulnerability in the SSL VPN negotiation process for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could…

PriorityP277high7.5CVSS 3.1
AVNACLPRNUINSUCNINAH
ITWVulnCheck KEV
Exploited in the wild
EPSS
1.85%
76.8th percentile
A vulnerability in the SSL VPN negotiation process for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to inefficient direct memory access (DMA) memory management during the negotiation phase of an SSL VPN connection. An attacker could exploit this vulnerability by sending a steady stream of crafted Datagram TLS (DTLS) traffic to an affected device. A successful exploit could allow the attacker to exhaust DMA memory on the device and cause a DoS condition.

Affected

13 ranges
VendorProductVersion rangeFixed in
ciscoadaptive_security_appliance< 9.6.4.459.6.4.45
ciscoadaptive_security_appliance
ciscoadaptive_security_appliance_software>= 9.10.0 < 9.10.1.449.10.1.44
ciscoadaptive_security_appliance_software>= 9.12.0 < 9.12.4.49.12.4.4
ciscoadaptive_security_appliance_software>= 9.13.0 < 9.13.1.139.13.1.13
ciscoadaptive_security_appliance_software>= 9.14.0 < 9.14.1.309.14.1.30
ciscoadaptive_security_appliance_software>= 9.8.0 < 9.8.4.299.8.4.29
ciscoadaptive_security_appliance_software>= 9.9.0 < 9.9.2.809.9.2.80
ciscocisco_adaptive_security_appliance_software
ciscofirepower_threat_defense< 6.3.0.66.3.0.6
ciscofirepower_threat_defense>= 6.4.0 < 6.4.0.106.4.0.10
ciscofirepower_threat_defense>= 6.5.0 < 6.5.0.56.5.0.5
ciscofirepower_threat_defense>= 6.6.0 < 6.6.16.6.1

Detection & IOCsextracted from sources · hover to see the quote

  • Detect a steady stream of crafted DTLS (Datagram TLS) traffic directed at the SSL VPN negotiation endpoint of Cisco ASA/FTD devices, which is the attack vector for exhausting DMA memory.
  • Monitor Cisco ASA/FTD devices for unexpected reloads or DMA memory exhaustion events, particularly when SSL VPN is enabled, as these are indicators of successful exploitation.
  • Track Cisco Bug ID CSCvu59817 for patch status and affected version identification on ASA/FTD devices.
  • ·Fixed releases for ASA code trains 9.13 and 9.14 may themselves be affected by a separate related vulnerability (Cisco ASA Software SSL/TLS DoS); operators should consult the updated advisory before patching.
  • ·There are no workarounds available for this vulnerability; patching is the only remediation.

CVSS provenance

nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvdv2.05.0MEDIUMAV:N/AC:L/Au:N/C:N/I:N/A:P
vulncheck8.6HIGH
vendor_cisco8.6HIGH
CVEs like this are exactly what “Exploited This Week” covers.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.