Vulnerability Name:

CVE-2019-12677 (CCN-168131)

Assigned:2019-10-02
Published:2019-10-02
Updated:2022-05-25
Summary:A vulnerability in the Secure Sockets Layer (SSL) VPN feature of Cisco Adaptive Security Appliance (ASA) Software could allow an authenticated, remote attacker to cause a denial of service (DoS) condition that prevents the creation of new SSL/Transport Layer Security (TLS) connections to an affected device. The vulnerability is due to incorrect handling of Base64-encoded strings. An attacker could exploit this vulnerability by opening many SSL VPN sessions to an affected device. The attacker would need to have valid user credentials on the affected device to exploit this vulnerability. A successful exploit could allow the attacker to overwrite a special system memory location, which will eventually result in memory allocation errors for new SSL/TLS sessions to the device, preventing successful establishment of these sessions. A reload of the device is required to recover from this condition. Established SSL/TLS connections to the device and SSL/TLS connections through the device are not affected.
Note: Although this vulnerability is in the SSL VPN feature, successful exploitation of this vulnerability would affect all new SSL/TLS sessions to the device, including management sessions.
CVSS v3 Severity:6.5 Medium (CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
5.7 Medium (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): High
7.7 High (CCN CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H)
6.7 Medium (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope:Scope (S): Changed
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): High
CVSS v2 Severity:4.0 Medium (CVSS v2 Vector: AV:N/AC:L/Au:S/C:N/I:N/A:P)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Authentication (Au): Single_Instance
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Partial
6.8 Medium (CCN CVSS v2 Vector: AV:N/AC:L/Au:S/C:N/I:N/A:C)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Athentication (Au): Single_Instance
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Complete
Vulnerability Type:CWE-755
Vulnerability Consequences:Denial of Service
References:Source: MITRE
Type: CNA
CVE-2019-12677

Source: XF
Type: UNKNOWN
cisco-cve201912677-dos(168131)

Source: CCN
Type: Cisco Security Advisory cisco-sa-20191002-asa-ssl-vpn-dos
Cisco Adaptive Security Appliance Software SSL VPN Denial of Service Vulnerability

Source: CISCO
Type: Vendor Advisory
20191002 Cisco Adaptive Security Appliance Software SSL VPN Denial of Service Vulnerability

Vulnerable Configuration:Configuration 1:
  • cpe:/a:cisco:adaptive_security_appliance:*:*:*:*:*:*:*:* (Version < 9.1.7.4)
  • OR cpe:/a:cisco:adaptive_security_appliance:*:*:*:*:*:*:*:* (Version >= 9.2 and < 9.2.4.8)
  • OR cpe:/a:cisco:adaptive_security_appliance:*:*:*:*:*:*:*:* (Version >= 9.4 and < 9.4.2.11)
  • OR cpe:/a:cisco:adaptive_security_appliance:*:*:*:*:*:*:*:* (Version >= 9.5 and < 9.5.2.5)
  • OR cpe:/a:cisco:adaptive_security_appliance:*:*:*:*:*:*:*:* (Version >= 9.6 and < 9.6.2)
  • OR cpe:/a:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:* (Version >= 9.3 and < 9.3.3.9)
  • AND
  • cpe:/h:cisco:asa_5585-x:-:*:*:*:*:*:*:*
  • OR cpe:/h:cisco:asa_5512-x:-:*:*:*:*:*:*:*
  • OR cpe:/h:cisco:asa_5515-x:-:*:*:*:*:*:*:*
  • OR cpe:/h:cisco:asa_5525-x:-:*:*:*:*:*:*:*
  • OR cpe:/h:cisco:asa_5555-x:-:*:*:*:*:*:*:*
  • OR cpe:/h:cisco:asa_5510:-:*:*:*:*:*:*:*
  • OR cpe:/h:cisco:asa_5550:-:*:*:*:*:*:*:*
  • OR cpe:/h:cisco:asa_5580:-:*:*:*:*:*:*:*
  • OR cpe:/h:cisco:asa_5505:-:*:*:*:*:*:*:*
  • OR cpe:/h:cisco:asa_5520:-:*:*:*:*:*:*:*

    • Configuration CCN 1:
  • cpe:/a:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*

    • * Denotes that component is vulnerable
    BACK
    cisco adaptive security appliance *
    cisco adaptive security appliance *
    cisco adaptive security appliance *
    cisco adaptive security appliance *
    cisco adaptive security appliance *
    cisco adaptive security appliance software *
    cisco asa 5585-x -
    cisco asa 5512-x -
    cisco asa 5515-x -
    cisco asa 5525-x -
    cisco asa 5555-x -
    cisco asa 5510 -
    cisco asa 5550 -
    cisco asa 5580 -
    cisco asa 5505 -
    cisco asa 5520 -
    cisco adaptive security appliance software *