Juniper SRX SG VPN Security Technical Implementation Guide

U_Juniper_SRX_SG_VPN_STIG_V1R1_Manual-xccdf.xml

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 e-mail to the following address: [email protected]
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Version / Release: V1R1

Published: 2016-04-01

Updated At: 2018-09-23 02:56:55

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Vuln Rule Version CCI Severity Title Description
SV-80511r1_rule JUSX-VN-000005 CCI-000068 HIGH The Juniper SRX Services Gateway VPN must use AES encryption for the IPsec proposal 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. The Advance Encryption Standard (AES) encryption is critical to ensuring the privacy of the IPsec session; it is imperative that AES is used for encryption operations. Remote access is access to DoD-non-public information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include broadband and wireless connections. While there is much debate about the security and performance of AES, there is a consensus that AES is significantly more secure than other algorithms currently supported by IPsec implementations. AES is available in three key sizes: 128, 192, and 256 bits, versus the 56 bit DES. Therefore, there are approximately 1021 times more AES 128-bit keys than DES 56-bit keys. In addition, AES uses a block size of 128 bits—twice the size of DES or 3DES.
SV-81107r1_rule JUSX-VN-000006 CCI-000068 HIGH The Juniper SRX Services Gateway VPN must use AES encryption for the Internet Key Exchange (IKE) proposal 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. The Advance Encryption Standard (AES) algorithm is critical to ensuring the privacy of the IKE session responsible for establishing the security association and key exchange for an IPsec tunnel. AES is used for encryption operations. Remote access is access to DoD-non-public information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Remote access methods include broadband and wireless connections. While there is much debate about the security and performance of AES, there is a consensus that AES is significantly more secure than other algorithms currently supported by IPsec implementations. AES is available in three key sizes: 128, 192, and 256 bits, versus the 56 bit DES. Therefore, there are approximately 1021 times more AES 128-bit keys than DES 56-bit keys. In addition, AES uses a block size of 128 bits—twice the size of DES or 3DES.
SV-81109r1_rule JUSX-VN-000010 CCI-000366 HIGH The Juniper SRX Services Gateway VPN must use Internet Key Exchange (IKE) for IPsec VPN Security Associations (SAs). Without IKE, the 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 Internet Key Exchange (IKE) or manual configuration. When using IKE, the security associations are established when needed and expire after a period of time or volume of traffic threshold. If manually configured, they are established as soon as the configuration is complete at both end points and they do not expire. When using IKE, the Security Parameter Index (SPI) for each security association is a pseudo-randomly derived number. With manual configuration of the IPsec security association, both the cipher key and authentication key are static. Hence, if the keys are compromised, the traffic being protected by the current IPsec tunnel can be decrypted as well as traffic in any future tunnels established by this SA. Furthermore, the peers are not authenticated prior to establishing the SA, which could result in a rogue device establishing an IPsec SA with either of the VPN end points. IKE provides primary authentication to verify the identity of the remote system before negotiation begins. This feature is lost when the IPsec security associations are manually configured, which results in a non-terminating session using static pre-shared keys.
SV-81111r1_rule JUSX-VN-000012 CCI-000366 HIGH The Juniper SRX Services Gateway VPN must 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. To achieve this, a list of certificates that have been revoked, known as a Certificate Revocation List (CRL), is sent periodically from the CA to the IPsec gateway. When an incoming Internet Key Exchange (IKE) session is initiated for a remote client or peer whose certificate is revoked, the CRL will be checked to see if the certificate is valid; if the certificate is revoked, IKE will fail and an IPsec security association will not be established for the remote endpoint.
SV-81113r1_rule JUSX-VN-000019 CCI-000766 HIGH The Juniper SRX Services Gateway VPN must use multifactor authentication (e.g., DoD PKI) for network access to non-privileged accounts. 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 know (e.g., password/PIN); (ii) Something you have (e.g., cryptographic identification device, token); or (iii) Something you are (e.g., biometric). A non-privileged account is any information system account with authorizations of a non-privileged user. Network access is any access to an application by a user (or process acting on behalf of a user) where said access is obtained through a network connection. The DoD CAC with DoD-approved PKI is an example of multifactor authentication.
SV-81115r1_rule JUSX-VN-000023 CCI-002450 HIGH The Juniper SRX Services Gateway VPN Internet Key Exchange (IKE) must use cryptography that is compliant with Suite B parameters 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 network element must implement cryptographic modules adhering to the higher standards approved by the federal government since this provides assurance they have been tested and validated. RFC 6379 Suite B Cryptographic Suites for IPsec defines four cryptographic user interface suites for deploying IPsec. Each suite provides choices for Encapsulating Security Payload (ESP) and IKE. The four suites are differentiated by the choice of IKE authentication and key exchange, cryptographic algorithm strengths, and whether ESP is to provide both confidentiality and integrity or integrity only. The suite names are based on the Advanced Encryption Standard (AES) mode and AES key length specified for ESP. Two suites are defined for transporting classified information up to SECRET level—one for both confidentiality and integrity and one for integrity only. There are also two suites defined for transporting classified information up to TOP SECRET level.
SV-81119r1_rule JUSX-VN-000001 CCI-000054 MEDIUM The Juniper SRX Services Gateway VPN must limit the number of concurrent sessions for user accounts to one (1) and administrative accounts to three (3), or set to an organization-defined number. Network element management includes the ability to control the number of users and user sessions that utilize a network element. Limiting the number of allowed users and sessions per user is helpful in limiting risks related to DoS attacks. This requirement addresses concurrent sessions for information system accounts and does not address concurrent sessions by single users via multiple system accounts. The maximum number of concurrent sessions should be defined based upon mission needs and the operational environment for each system. The intent of this policy is to ensure the number of concurrent sessions is deliberately set to a number based on the site's mission and not left unlimited.
SV-81121r1_rule JUSX-VN-000002 CCI-002361 MEDIUM The Juniper SRX Services Gateway VPN must renegotiate the security association after 8 hours or less. The IPsec 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 for use when the old one expires. The longer the lifetime of the IPsec SA, the longer the lifetime of the session key used to protect IP traffic. The SA is less secure with a longer lifetime because an attacker has a greater opportunity to collect traffic encrypted by the same key and subject it to cryptanalysis. However, a shorter lifetime causes IPsec peers to renegotiate Phase II more often resulting in the expenditure of additional resources. For the Juniper SRX, specify the lifetime (in seconds) of an Internet Key Exchange (IKE) security association (SA). When the SA expires, it is replaced by a new SA, the security parameter index (SPI), or terminated if the peer cannot be contacted for renegotiation.
SV-81131r1_rule JUSX-VN-000025 CCI-001184 HIGH The Juniper SRX Services Gateway VPN must configure Internet Key Exchange (IKE) with SHA1 or greater to protect the authenticity of communications sessions. Authenticity protection provides protection against man-in-the-middle attacks/session hijacking and the insertion of false information into sessions. This requirement focuses on communications protection for the application session rather than for the network packet and establishes grounds for confidence at both ends of communications sessions in ongoing identities of other parties and in the validity of information transmitted. Depending on the required degree of confidentiality and integrity, web services/SOA will require the use of mutual authentication (two-way/bidirectional). An IPsec Security Associations (SA) is established using either IKE or manual configuration.
SV-81133r1_rule JUSX-VN-000003 CCI-002361 MEDIUM The Juniper SRX Services Gateway VPN must renegotiate the 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 Key Exchange (IKE) idle timeout may also be set to allow SAs associated with inactive endpoints to be deleted before the SA lifetime has expired, although this setting is not recommended at this time. The value of one hour or less is a common best practice.
SV-81135r1_rule JUSX-VN-000004 CCI-000067 MEDIUM The Juniper SRX Services Gateway VPN device also fulfills the role of IDPS in the architecture, the device must inspect the VPN traffic in compliance with DoD IDPS requirements. Remote access devices, such as those providing remote access to network devices and information systems, which lack automated, capabilities increase risk and makes remote user access management difficult at best. Remote access is access to DoD non-public information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Automated monitoring of remote access sessions allows organizations to detect cyber attacks and also ensure ongoing compliance with remote access policies by auditing connection activities of remote access capabilities, from a variety of information system components (e.g., servers, workstations, notebook computers, smart phones, and tablets).
SV-81137r1_rule JUSX-VN-000007 CCI-000068 MEDIUM The Juniper SRX Services Gateway VPN must implement a FIPS-140-2 validated Diffie-Hellman (DH) group. Use of an approved DH algorithm ensures the Internet Key Exchange (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 in which the key was derived from. Hence, the larger the modulus, the more secure the generated key is considered to be.
SV-81139r1_rule JUSX-VN-000008 CCI-001453 MEDIUM The Juniper SRX Services Gateway VPN must be configured to use IPsec with SHA1 or greater to negotiate hashing to protect the integrity of remote access sessions. Without strong cryptographic integrity protections, information can be altered by unauthorized users without detection. Remote access VPN provides access to DoD non-public information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network.
SV-81141r1_rule JUSX-VN-000009 CCI-001414 MEDIUM The Juniper SRX Services Gateway VPN must ensure inbound and outbound traffic is configured with a security policy in compliance with information flow control policies. Remote access devices, such as those providing remote access to network devices and information systems, which lack automated, capabilities increase risk and makes remote user access management difficult at best. Remote access is access to DoD non-public information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Automated monitoring of remote access sessions allows organizations to detect cyber attacks and also ensure ongoing compliance with remote access policies by auditing connection activities of remote access capabilities, from a variety of information system components (e.g., servers, workstations, notebook computers, smart phones, and tablets). In phase-2, another negotiation is performed, detailing the parameters for the IPsec connection. New keying material using the Diffie-Hellman key exchange established in phase-1 is used to provide session keys used to protecting the VPN data flow. If Perfect-Forwarding-Secrecy (PFS) is used, a new Diffie-Hellman exchange is performed for each phase-2 negotiation. While this is slower, it makes sure that no keys are dependent on any other previously used keys; no keys are extracted from the same initial keying material. This is to make sure that, in the unlikely event that some key was compromised; no subsequent keys can be derived.
SV-81143r1_rule JUSX-VN-000011 CCI-000366 MEDIUM If IDPS inspection is performed separately from the Juniper SRX Services Gateway VPN device, the VPN must route sessions to an IDPS for inspection. Remote access devices, such as those providing remote access to network devices and information systems, which lack automated, capabilities increase risk and makes remote user access management difficult at best. Remote access is access to DoD non-public information systems by an authorized user (or an information system) communicating through an external, non-organization-controlled network. Automated monitoring of remote access sessions allows organizations to detect cyber attacks and also ensure ongoing compliance with remote access policies by auditing connection activities of remote access capabilities, from a variety of information system components (e.g., servers, workstations, notebook computers, smart phones, and tablets).
SV-81145r1_rule JUSX-VN-000013 CCI-000366 MEDIUM The Juniper SRX Services Gateway VPN must specify Perfect Forward Secrecy (PFS). 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 rekey can be performed with or without Perfect Forward Secrecy (PFS). With PFS, every time a new IPsec Security Association is negotiated during the Quick Mode, a new Diffie-Hellman (DH) exchange occurs. The new DH shared secret will be included with original keying material (SYKEID_d, initiator nonce, and responder nonce from phase 1) for generating a new IPsec session key. If PFS is not used, the IPsec session key will always be completely dependent on the original keying material from the Phase-1. Hence, if an older key is compromised at any time, it is possible that all new keys may be compromised. The DH exchange is performed in the same manner as was done in phase 1 (Main or Aggressive Mode). However, the phase 2 exchange is protected by encrypting the phase 2 packets with the key derived from the phase 1 negotiation. Because DH negotiations during phase 2 are encrypted, the new IPsec session key has an added element of secrecy.
SV-81147r1_rule JUSX-VN-000014 CCI-000366 MEDIUM The Juniper SRX Services Gateway VPN must use Encapsulating Security Payload (ESP) in tunnel mode. ESP provides confidentiality, data origin authentication, integrity, and anti-replay services within the IPsec suite of protocols. ESP in tunnel mode ensures a secure path for communications for site-to-site VPNs and gateway to endpoints, including header information. ESP can be deployed in either transport or tunnel mode. Transport mode is used to create a secured session between two hosts. It can also be used when two hosts simply want to authenticate each IP packet with IPsec authentication header (AH). With ESP transport mode, only the payload (transport layer) is encrypted, whereas with tunnel mode, the entire IP packet is encrypted and encapsulated with a new IP header. Tunnel mode is used to encrypt traffic between secure IPsec gateways or between an IPsec gateway and an end-station running IPsec software. Hence, it is the only method to provide a secured path to transport traffic between remote sites or end-stations and the central site.
SV-81149r1_rule JUSX-VN-000015 CCI-000381 MEDIUM The Juniper SRX Services Gateway must disable or remove unnecessary network services and functions that are not used as part of its role in the architecture. Network devices are capable of providing a wide variety of functions (capabilities or processes) and services. Some of these functions and services are installed and enabled by default. The organization must determine which functions and services are required to perform the content filtering and other necessary core functionality for each component of the SRX. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Services that may be related security-related, but based on the role of the device in the architecture do not need to be installed. For example, the Juniper SRX can have an Antivirus, Web filter, IDS, or ALG license. However, if these functions are not part of the documented role of the SRX in the enterprise or branch architecture, then these the software and licenses should not be installed on the device. This mitigates the risk of exploitation of unconfigured services or services that are not kept updated with security fixes. If left unsecured, these services may provide a threat vector. Only remove unauthorized services. This control is not intended to restrict the use of Juniper SRX devices with multiple authorized roles.
SV-81151r1_rule JUSX-VN-000016 CCI-000382 MEDIUM The Juniper SRX Services Gateway VPN must use IKEv2 for IPsec VPN security associations. Use of IKEv2 leverages DoS protections because of improved bandwidth management and leverages more secure encryption algorithms.
SV-81153r1_rule JUSX-VN-000017 CCI-000382 MEDIUM The Juniper SRX Services Gateway VPN must be configured to prohibit or restrict the use of functions, ports, protocols, and/or services, as defined in the PPSM CAL and vulnerability assessments. 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. DoD continually assesses the ports, protocols, and services that can be used for network communications. Some ports, protocols or services have known exploits or security weaknesses. Network traffic using these ports, protocols, and services must be prohibited or restricted in accordance with DoD policy. The PPSM CAL and vulnerability assessments provide an authoritative source for ports, protocols, and services that are unauthorized or restricted across boundaries on DoD networks. The Juniper SRX must be configured to prevent or restrict the use of prohibited ports, protocols, and services throughout the network by filtering the network traffic and disallowing or redirecting traffic as necessary. Default and updated policy filters from the vendors will disallow older version of protocols and applications and will address most known non-secure ports, protocols, and/or services.
SV-81155r1_rule JUSX-VN-000018 CCI-000764 MEDIUM The Juniper SRX Services Gateway VPN must uniquely identify and authenticate organizational users (or processes acting on behalf of organizational users). 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 users) must be uniquely identified and authenticated for all accesses except the following. (i) Accesses explicitly identified and documented by the organization. Organizations document specific user actions that can be performed on the information system without identification or authentication; and (ii) Accesses that occur through authorized use of group authenticators without individual authentication. Organizations may require unique identification of individuals in group accounts (e.g., shared privilege accounts) or for detailed accountability of individual activity. This requirement only applies to components where this is specific to the function of the device or has the concept of an organizational user (e.g., VPN or proxy capability). This does not apply to authentication for the purpose of configuring the device itself (i.e., device management).
SV-81157r1_rule JUSX-VN-000020 CCI-000803 MEDIUM The Juniper SRX Services Gateway VPN must use FIPS 140-2 compliant mechanisms for authentication to a cryptographic module. Unapproved mechanisms that are used for authentication to the cryptographic module are not verified, and therefore cannot be relied upon to provide confidentiality or integrity and DoD data may be compromised. Network elements utilizing encryption are required to use FIPS compliant mechanisms for authenticating to cryptographic modules. FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules utilize authentication that meets DoD requirements.
SV-81159r1_rule JUSX-VN-000021 CCI-000804 MEDIUM The Juniper SRX Services Gateway VPN must uniquely identify and authenticate non-organizational users (or processes acting on behalf of non-organizational users). Lack of authentication and identification enables non-organizational users to gain access to the network or possibly a network element that provides opportunity for intruders to compromise resources within the network infrastructure. This requirement only applies to components where this is specific to the function of the device or has the concept of a non-organizational user.
SV-81161r1_rule JUSX-VN-000024 CCI-002450 MEDIUM The Juniper SRX Services Gateway VPN IKE must use NIST FIPS-validated cryptography to implement encryption services for unclassified VPN traffic. Use of weak or untested encryption algorithms undermines the purposes of utilizing encryption to protect data. The network element must implement cryptographic modules adhering to the higher standards approved by the federal government since this provides assurance they have been tested and validated.
SV-81163r1_rule JUSX-VN-000026 CCI-002470 MEDIUM The Juniper SRX Services Gateway VPN must only allow the use of DoD PKI established certificate authorities for verification of the establishment of protected sessions. Untrusted certificate authorities (CA) can issue certificates, but they may be issued by organizations or individuals that seek to compromise DoD systems or by organizations with insufficient security controls. If the CA used for verifying the certificate is not a DoD-approved CA, trust of this CA has not been established. The DoD will only accept PKI certificates obtained from a DoD-approved internal or external certificate authority. Reliance on CAs for the establishment of secure sessions includes, for example, the use of Internet Key Exchange (IKE) authentication certificates. This requirement focuses on communications protection for the application session rather than for the network packet. Network elements that perform these functions must be able to identify which session identifiers were generated when the sessions were established.
SV-81165r1_rule JUSX-VN-000027 CCI-002403 MEDIUM The Juniper SRX Services Gateway VPN must only allow incoming VPN communications from organization-defined authorized sources routed to organization-defined authorized destinations. 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. Access control policies and access control lists implemented on devices, such as firewalls, that control the flow of network traffic, ensure the flow of traffic is only allowed from authorized sources to authorized destinations. Networks with different levels of trust (e.g., the Internet) must be kept separated.
SV-81167r1_rule JUSX-VN-000028 CCI-002397 MEDIUM The Juniper SRX Services Gateway VPN must disable split-tunneling for remote clients VPNs. 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 access to the Internet while at the same time has established a secured path to the enclave via an IPsec tunnel. A remote client connected to the Internet that has been compromised by an attacker in the Internet, provides an attack base to the enclave’s private network via the IPsec tunnel. Hence, it is imperative that the VPN gateway enforces a no split-tunneling policy to all remote clients. Traffic to the protected resource will go through the specified dynamic VPN tunnel and will therefore be protected by the Juniper SRX firewall’s security policies.
SV-81169r1_rule JUSX-VN-000031 CCI-001942 MEDIUM The Juniper SRX Services Gateway VPN must use anti-replay mechanisms for security associations. Anti-replay is an IPsec security mechanism at a packet level which helps to avoid unwanted users from intercepting and modifying an ESP packet. The SRX adds a sequence number to the ESP encapsulation which is verified by the VPN peer so packets are received within a correct sequence. This will cause issues if packets are not received in the order in which they were sent out. By default the SRX has a replay window of 64 or 32, depending on the platform. The SRX drops packets received out of order that are not received within this window. However, this default may be overridden by setting the option no-anti-replay as follows: set security vpn name ike no-anti-replay.
SV-81171r1_rule JUSX-VN-000022 CCI-001133 LOW The Juniper SRX Services Gateway VPN must terminate all network connections associated with a communications session at the end of the session. Idle TCP sessions can be susceptible to unauthorized access and hijacking attacks. By default, routers do not continually test whether a previously connected TCP endpoint is still reachable. If one end of a TCP connection idles out or terminates abnormally, the opposite end of the connection may still believe the session is available. These “orphaned” sessions use up valuable router resources and can also be hijacked by an attacker. To mitigate this risk, routers must be configured to send periodic keep alive messages to check that the remote end of a session is still connected. If the remote device fails to respond to the TCP keep alive message, the sending router will clear the connection and free resources allocated to the session. The TCP keep-alive for remote access is implemented in the Juniper SRX Firewall STIG.