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Cisco ASA VPN Security Technical Implementation Guide

Overview

Version Date Finding Count (41) Downloads
2 2024-08-22 CAT I (High): 10 CAT II (Medium): 28 CAT III (Low): 3 Excel JSON XML
Stig Description
This Security Technical Implementation Guide is published as a tool to improve the security of Department of Defense (DOD) information systems. The requirements are derived from the National Institute of Standards and Technology (NIST) 800-53 and related documents. Comments or proposed revisions to this document should be sent via email to the following address: disa.stig_spt@mail.mil.
Classified Public Sensitive  
I - Mission Critical Classified I - Mission Critical Public I - Mission Critical Sensitive II - Mission Critical Classified II - Mission Critical Public II - Mission Critical Sensitive III - Mission Critical Classified III - Mission Critical Public III - Mission Critical Sensitive

Findings - All

Finding ID Severity Title Description
V-268314 High The Cisco ASA must be configured to not accept certificates that have been revoked when using PKI for authentication. Situations may arise in which the certificate issued by a Certificate Authority (CA) may need to be revoked before the lifetime of the certificate expires. For example, the certificate is known to have been compromised. When an incoming Internet Key Exchange (IKE) session is initiated for a remote client or...
V-239985 High The Cisco ASA VPN remote access server must be configured to use an approved High Assurance Commercial Solution for Classified (CSfC) cryptographic algorithm for remote access to a classified network. Use of improperly configured or lower assurance equipment and solutions could compromise high-value information. The National Security Agency/Central Security Service's (NSA/CSS) CSfC program enables commercial products to be used in layered solutions to protect classified National Security Systems (NSS) data. Based on an analysis of the impact of quantum computing,...
V-239980 High The Cisco ASA VPN remote access server must be configured to use AES256 or greater encryption for the IPsec security association to protect the confidentiality of remote access sessions. Without confidentiality protection mechanisms, unauthorized individuals may gain access to sensitive information via a remote access session. Remote access is access to DOD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. A block cipher mode is an algorithm that features the...
V-239979 High The Cisco VPN remote access server must be configured to use AES256 or greater encryption for the Internet Key Exchange (IKE) Phase 1 to protect confidentiality of remote access sessions. Without confidentiality protection mechanisms, unauthorized individuals may gain access to sensitive information via a remote access session. Remote access is access to DOD nonpublic information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. AES is the FIPS-validated cipher block cryptographic algorithm approved for...
V-239975 High The Cisco ASA remote access VPN server must be configured to use TLS 1.2 or higher to protect the confidentiality of remote access connections. Using older unauthorized versions or incorrectly configuring protocol negotiation makes the gateway vulnerable to known and unknown attacks that exploit vulnerabilities in this protocol. NIST SP 800-52 provides guidance for client negotiation on either DoD-only or public-facing servers.
V-239968 High The Cisco ASA remote access VPN server must be configured to enforce certificate-based authentication before granting access to the network. To assure accountability and prevent unauthenticated access, non-privileged users must utilize multifactor authentication to prevent potential misuse and compromise of the system. Multifactor authentication uses two or more factors to achieve authentication. Use of password for user remote access for non-privileged account is not authorized. Factors include: (i) Something you...
V-239962 High The Cisco ASA VPN gateway must use cryptographic algorithms approved by NSA to protect NSS when transporting classified traffic across an unclassified network. Use of weak or untested encryption algorithms undermines the purposes of utilizing encryption to protect data. The VPN gateway must implement cryptographic modules adhering to the higher standards approved by the Federal Government since this provides assurance they have been tested and validated. NIST cryptographic algorithms are approved by NSA...
V-239959 High The Cisco ASA must be configured to use FIPS-validated SHA-2 or higher for Internet Key Exchange (IKE) Phase 2. Authenticity protection provides protection against man-in-the-middle attacks/session hijacking and the insertion of false information into sessions. Although allowed by SP800-131Ar2 for some applications, SHA-1 is considered a compromised hashing standard and is being phased out of use by industry and government standards. Unless required for legacy use, DOD systems should...
V-239957 High The Cisco ASA must be configured to use a Diffie-Hellman (DH) Group of 16 or greater for Internet Key Exchange (IKE) Phase 1. Use of an approved DH algorithm ensures the IKE (Phase 1) proposal uses FIPS-validated key management techniques and processes in the production, storage, and control of private/secret cryptographic keys. The security of the DH key exchange is based on the difficulty of solving the discrete logarithm from which the key...
V-239951 High The Cisco ASA must be configured to use Internet Key Exchange (IKE) for all IPsec security associations. Without IKE, the Security Parameter Index (SPI) is manually specified for each security association. IKE peers will negotiate the encryption algorithm and authentication or hashing methods as well as generate the encryption keys. An IPsec SA is established using either IKE or manual configuration. When using IKE, the security associations...
V-239984 Medium The Cisco ASA VPN remote access server must be configured to validate certificates used for Transport Layer Security (TLS) functions by performing RFC 5280-compliant certification path validation. A certificate's certification path is the path from the end entity certificate to a trusted root certification authority (CA). Certification path validation is necessary for a relying party to make an informed decision regarding acceptance of an end entity certificate. Certification path validation includes checks such as certificate issuer trust,...
V-239983 Medium The Cisco ASA VPN remote access server must be configured to generate log records when successful and/or unsuccessful VPN connection attempts occur. Without generating log records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident, or identify those responsible for one. Log records can be generated from various components within the information system (e.g.,...
V-239982 Medium The Cisco ASA VPN remote access server must be configured to disable split-tunneling for remote clients. Split tunneling would in effect allow unauthorized external connections, making the system more vulnerable to attack and to exfiltration of organizational information. A VPN hardware or software client with split tunneling enabled provides an unsecured backdoor to the enclave from the internet. With split tunneling enabled, a remote client has...
V-239981 Medium The Cisco VPN remote access server must be configured to accept Common Access Card (CAC) credential credentials. The use of PIV credentials facilitates standardization and reduces the risk of unauthorized access. DoD has mandated the use of the CAC to support identity management and personal authentication for systems covered under HSPD 12, as well as a primary component of layered protection for national security systems.
V-239978 Medium The Cisco ASA remote access VPN server must be configured to use SHA-2 at 384 bits or greater for hashing to protect the integrity of IPsec remote access sessions. Without strong cryptographic integrity protections, information can be altered by unauthorized users without detection. SHA-1 is considered a compromised hashing standard and is being phased out of use by industry and Government standards. DOD systems must not be configured to use SHA-1 for integrity of remote access sessions. The remote...
V-239977 Medium The Cisco ASA remote access VPN server must be configured to generate unique session identifiers using a FIPS-validated Random Number Generator (RNG) based on the Deterministic Random Bit Generators (DRBG) algorithm. Both IPsec and TLS gateways use the RNG to strengthen the security of the protocols. Using a weak RNG will weaken the protocol and make it more vulnerable. Use of a FIPS validated RNG that is not DRGB mitigates to a CAT III.
V-239976 Medium The Cisco ASA remote access VPN server must be configured to use a FIPS-validated algorithm and hash function to protect the integrity of TLS remote access sessions. Without integrity protection, unauthorized changes may be made to the log files and reliable forensic analysis and discovery of the source of malicious system activity may be degraded. Remote access (e.g., RDP) is access to DoD nonpublic information systems by an authorized user (or an information system) communicating through an...
V-239974 Medium The Cisco ASA remote access VPN server must be configured to produce log records containing information to establish the outcome of the events. Without information about the outcome of events, security personnel cannot make an accurate assessment as to whether an attack was successful or if changes were made to the security state of the network. Event outcomes can include indicators of event success or failure and event-specific results (e.g., the security state...
V-239972 Medium The Cisco ASA remote access VPN server must be configured to generate log records containing information to establish where the events occurred. Without establishing where events occurred, it is impossible to establish, correlate, and investigate the events leading up to an outage or attack. In order to compile an accurate risk assessment, and provide forensic analysis, it is essential for security personnel to know where events occurred, such as VPN gateway components,...
V-239971 Medium The Cisco ASA remote access VPN server must be configured to generate log records containing information that establishes the identity of any individual or process associated with the event. Without information that establishes the identity of the subjects (i.e., users or processes acting on behalf of users) associated with the events, security personnel cannot determine responsibility for the potentially harmful event.
V-239970 Medium The Cisco ASA remote access VPN server must be configured to display the Standard Mandatory DoD Notice and Consent Banner before granting access to the network.
V-239969 Medium The Cisco ASA remote access VPN server must be configured to map the distinguished name (DN) from the client’s certificate to entries in the authentication server to determine authorization to access the network. Without mapping the certificate used to authenticate to the user account, the ability to determine the identity of the individual user or group will not be available for forensic analysis. This requirement only applies to components where this is specific to the function of the device or has the concept...
V-239967 Medium The Cisco ASA remote access VPN server must be configured to identify and authenticate users before granting access to the network. To assure accountability and prevent unauthenticated access, organizational users must be identified and authenticated to prevent potential misuse and compromise of the system. Organizational users include organizational employees or individuals the organization deems to have equivalent status of employees (e.g., contractors). Organizational users (and any processes acting on behalf of...
V-239966 Medium The Cisco ASA remote access VPN server must be configured to use LDAP over SSL to determine authorization for granting access to the network. Protecting authentication communications between the client, the VPN Gateway, and the authentication server keeps this critical information from being exploited. In distributed information systems, authorization processes and access control decisions may occur in separate parts of the systems. In such instances, authorization information is transmitted securely so timely access control...
V-239965 Medium The Cisco ASA remote access VPN server must be configured to use a separate authentication server than that used for administrative access. The VPN interacts directly with public networks and devices and should not contain user authentication information for all users. AAA network security services provide the primary framework through which a network administrator can set up access control and authorization on network points of entry or network access servers. It is...
V-239964 Medium The Cisco ASA VPN gateway must be configured to renegotiate the IKE security association after 24 hours or less. When a VPN gateway creates an IPsec security association (SA), resources must be allocated to maintain the SA. These resources are wasted during periods of IPsec endpoint inactivity, which could result in the gateway’s inability to create new SAs for other endpoints, thereby preventing new sessions from connecting. The Internet...
V-239963 Medium The Cisco ASA VPN gateway must be configured to renegotiate the IPsec Security Association after eight hours or less. The IPsec security association (SA) and its corresponding key will expire either after the number of seconds or amount of traffic volume has exceeded the configured limit. A new SA is negotiated before the lifetime threshold of the existing SA is reached to ensure that a new SA is ready...
V-239961 Medium The Cisco ASA VPN gateway must be configured to identify all peers before establishing a connection. Without identifying devices, unidentified or unknown devices may be introduced, thereby facilitating malicious activity. For distributed architectures (e.g., service-oriented architectures), the decisions regarding the validation of identification claims may be made by services separate from the services acting on those decisions. In such situations, it is necessary to provide the...
V-239960 Medium The Cisco ASA VPN gateway must be configured to restrict what traffic is transported via the IPsec tunnel according to flow control policies. Unrestricted traffic may contain malicious traffic which poses a threat to an enclave or to other connected networks. Additionally, unrestricted traffic may transit a network, which uses bandwidth and other resources. VPN traffic received from another enclave with different security policy or level of trust must not bypass being inspected...
V-239958 Medium The Cisco ASA must be configured to use FIPS-validated SHA-2 at 384 bits or higher for Internet Key Exchange (IKE) Phase 1. Without cryptographic integrity protections, information can be altered by unauthorized users without detection. Although allowed by SP800-131Ar2 for some applications, SHA-1 is considered a compromised hashing standard and is being phased out of use by industry and government standards. Unless required for legacy use, DOD systems should not be configured...
V-239956 Medium The Cisco ASA must be configured to use a FIPS-validated cryptographic module to implement IPsec encryption services. FIPS 140-2/140-3 precludes the use of invalidated cryptography for the cryptographic protection of sensitive or valuable data within federal systems. Unvalidated cryptography is viewed by NIST as providing no protection to the information or data. In effect, the data would be considered unprotected plain text. If the agency specifies that...
V-239955 Medium The Cisco ASA must be configured to use a FIPS-validated cryptographic module to generate cryptographic hashes. FIPS 140-2/140-3 precludes the use of invalidated cryptography for the cryptographic protection of sensitive or valuable data within federal systems. Unvalidated cryptography is viewed by NIST as providing no protection to the information or data. In effect, the data would be considered unprotected plain text. If the agency specifies that...
V-239954 Medium The Cisco ASA must be configured to specify Perfect Forward Secrecy (PFS) for the IPsec Security Association (SA) during IKE Phase 2 negotiation. PFS generates each new encryption key independently from the previous key. Without PFS, compromise of one key will compromise all communications. The Phase 2 (Quick Mode) Security Association (SA) is used to create an IPsec session key. Hence, its rekey or key regeneration procedure is very important. The Phase 2...
V-239953 Medium The Cisco ASA must be configured to use NIST FIPS-validated cryptography for Internet Key Exchange (IKE) Phase 1. Use of weak or untested encryption algorithms undermines the purposes of utilizing encryption to protect data. The VPN gateway must implement cryptographic modules adhering to the higher standards approved by the federal government since this provides assurance they have been tested and validated.
V-239952 Medium The Cisco ASA must be configured to use Internet Key Exchange v2 (IKEv2) for all IPsec security associations. In order to prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types); organizations must disable or restrict unused or unnecessary physical and logical ports/protocols on information systems. Use of IKEv2 leverages DoS protections because of improved bandwidth management and...
V-239949 Medium The Cisco ASA must be configured to validate certificates via a trustpoint that identifies a DoD or DoD-approved certificate authority. Without path validation, an informed trust decision by the relying party cannot be made when presented with any certificate not already explicitly trusted. To meet this requirement, the information system must create trusted channels between itself and remote trusted authorized IT product (e.g., syslog server) entities that protect the confidentiality...
V-239948 Medium The Cisco ASA must be configured to generate an alert that can be forwarded as an alert to organization-defined personnel and/or firewall administrator of all log failure events. It is critical for the appropriate personnel to be aware if a system is at risk of failing to process audit logs as required. Without a real-time alert, security personnel may be unaware of an impending failure of the audit capability and system operation may be adversely affected. Alerts provide...
V-239947 Medium The Cisco ASA must be configured to queue log records locally in the event that the central audit server is down or not reachable. If the system were to continue processing after audit failure, actions can be taken on the system that cannot be tracked and recorded for later forensic analysis. Because of the importance of ensuring mission/business continuity, organizations may determine that the nature of the audit failure is not so severe that...
V-239973 Low The Cisco ASA remote access VPN server must be configured to generate log records containing information to establish the source of the events. Without establishing the source of the event, it is impossible to establish, correlate, and investigate the events leading up to an outage or attack. In order to compile an accurate risk assessment and provide forensic analysis, security personnel need to know the source of the event. In addition to logging...
V-239946 Low The Cisco ASA must be configured to generate log records containing information to establish when the events occurred. Without establishing when events occurred, it is impossible to establish, correlate, and investigate the events leading up to an outage or attack. VPN gateways often have a separate audit log for capturing VPN status and other information about the traffic (as opposed to the log capturing administrative and configuration actions)....
V-239945 Low The Cisco ASA must be configured to generate log records containing information to establish what type of VPN events occurred. Without establishing what type of event occurred, it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack. VPN gateways often have a separate audit log for capturing VPN status and other information about the traffic (as opposed to the log capturing administrative...