Ivanti Sentry 9.x ALG Security Technical Implementation Guide

Successful authentication through Sentry must not automatically give an entity access to resources behind Sentry. The lack of authorization-based access control could result in the immediate compromise and unauthorized access to sensitive information. All DoD systems must be properly configured to incorporate access control methods that do not rely solely on authentication for authorized access.

Information flow control regulates where information is allowed to travel within a network. The flow of all network traffic must be monitored and controlled so it does not introduce any unacceptable risk to the network infrastructure or data. Sentry enforces approved authorizations by employing security policy and/or rules configured in MobileIron UEM that restrict information system services capability based on header or protocol information.

Information flow control regulates where information is allowed to travel within a network and between interconnected networks. Blocking or restricting detected harmful or suspicious communications between interconnected networks enforces approved authorizations for controlling the flow of traffic. This requirement applies to the flow of information between the Sentry when used as a gateway or boundary device which allows traffic flow between interconnected networks of differing security policies. The Sentry and MobileIron UEM must be configured with policy filters (e.g., security policy and compliance rules) that restrict or block information system services.

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. Remote access methods include broadband and wireless connections. Remote access methods include, for example, proxied remote encrypted traffic (e.g., TLS gateways, web content filters, and webmail proxies). Encryption provides a means to secure the remote connection so as to prevent unauthorized access to the data traversing the remote access connection, thereby providing a degree of confidentiality. The encryption strength of the mechanism is selected based on the security categorization of the information. This requirement applies to ALGs providing remote access proxy services as part of its intermediary services (e.g., OWA or TLS gateway).

Private key data is used to prove that the entity presenting a public key certificate is the certificate's rightful owner. Compromise of private key data allows an adversary to impersonate the key holder.

SP 800-52 provides guidance on using the most secure version and configuration of the TLS/SSL protocol. Using older unauthorized versions or incorrectly configuring protocol negotiation makes the gateway vulnerable to known and unknown attacks which exploit vulnerabilities in this protocol.

Without cryptographic integrity protections, information can be altered by unauthorized users without detection. 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. Remote access methods include broadband and wireless connections. Remote access methods include, for example, proxied remote encrypted traffic (e.g., TLS gateways, web content filters, and webmail proxies). Cryptographic mechanisms used for protecting the integrity of information include, for example, signed hash functions using asymmetric cryptography enabling distribution of the public key to verify the hash information while maintaining the confidentiality of the secret key used to generate the hash. This requirement applies to ALGs providing remote access proxy services as part of its intermediary services (e.g., OWA or TLS gateway).

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. ALGs are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. 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 ALG is a key network element for preventing these non-compliant ports, protocols, and services from causing harm to DoD information systems. The network ALG 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. However, sources for further policy filters are the IAVMs and the PPSM requirements. Satisfies: SRG-NET-000132-ALG-000087, SRG-NET-000512-ALG-000062

User account and privilege validation must be centralized in order to prevent unauthorized access using changed or revoked privileges. ALGs can implement functions such as traffic filtering, authentication, access, and authorization functions based on computer and user privileges. However, the directory service (e.g., Active Directory or LDAP) must not be installed on the ALG, particularly if the gateway resides on the untrusted zone of the Enclave.

User authentication can be used as part of the policy filtering rule sets. Some URLs or network resources can be restricted to authenticated users only. Users are prompted by the application or browser for credentials. Authentication service may be provided by the ALG as an intermediary for the application; however, the authentication credential must be stored in the site's directory services server. 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., proxy capability). This does not apply to authentication for the purpose of configuring the device itself (i.e., device management).

To ensure 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. Factors include: 1. Something you know (e.g., password/PIN) 2. Something you have (e.g., cryptographic, identification device, token) 3. Something you are (e.g., biometric) Non-privileged accounts are not authorized access to the network element regardless of access method. 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. Authenticating with a PKI credential and entering the associated PIN is an example of multifactor authentication. This requirement applies to ALGs that provide user authentication intermediary services.

A replay attack may enable an unauthorized user to gain access to the application. Authentication sessions between the authenticator and the application validating the user credentials must not be vulnerable to a replay attack. An authentication process resists replay attacks if it is impractical to achieve a successful authentication by recording and replaying a previous authentication message. A nonprivileged account is any account with the authorizations of a non-privileged user. Privileged roles are organization-defined roles assigned to individuals that allow those individuals to perform certain security-relevant functions that ordinary users are not authorized to perform. Security relevant roles include key management, account management, network and system administration, database administration, and web administration. Techniques used to address this include protocols using nonces (e.g., numbers generated for a specific one time use) or challenges (e.g., TLS). Additional techniques include time-synchronous or challenge-response one-time authenticators. This requirement applies to ALGs that provide user authentication intermediary services.

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, time validity and revocation status for each certificate in the certification path. Revocation status information for CA and subject certificates in a certification path is commonly provided via certificate revocation lists (CRLs) or online certificate status protocol (OCSP) responses.

Authorization for access to any network element requires an approved and assigned individual account identifier. To ensure only the assigned individual is using the account, the account must be bound to a user certificate when PKI-based authentication is implemented. This requirement applies to ALGs that provide user authentication intermediary services (e.g., authentication gateway or TLS gateway). This does not apply to authentication for the purpose of configuring the device itself (device management).

Terminating an idle session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been left unattended. In addition, quickly terminating an idle session will also free up resources committed by the managed network element. Terminating network connections associated with communications sessions includes, for example, de-allocating associated TCP/IP address/port pairs at the operating system level, and de-allocating networking assignments at the application level if multiple application sessions are using a single operating system level network connection. ALGs may provide session control functionality as part of content filtering, load balancing, or proxy services.

For remote access to nonprivileged accounts, the purpose of requiring a device that is separate from the information system gaining access for one of the factors during multifactor authentication is to reduce the likelihood of compromising authentication credentials stored on the system. Multifactor solutions that require devices separate from information systems gaining access include, for example, hardware tokens providing time-based or challenge-response authenticators and smart cards such as the U.S. Government Personal Identity Verification card and the DOD common access card. A privileged account is defined as an information system account with authorizations of a privileged user. 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. Remote access methods include, for example, dial-up, broadband, and wireless. An example of compliance with this requirement is the use of a one-time password token and PIN coupled with a password; or the use of a CAC/PIV card and PIN coupled with a password.

Non-DoD-approved PKIs have not been evaluated to ensure they have security controls and identity vetting procedures in place that are sufficient for DoD systems to rely on the identity asserted in the certificate. PKIs lacking sufficient security controls and identity vetting procedures risk being compromised and issuing certificates that enable adversaries to impersonate legitimate users. The authoritative list of DoD-approved PKIs is published at https://cyber.mil/pki-pke/interoperability. DoD-approved PKI CAs may include Category I, II, and III certificates. Category I DoD-approved External PKIs are PIV issuers. Category II DoD-approved External PKIs are Non-Federal Agency PKIs cross-certified with the Federal Bridge Certification Authority (FBCA). Category III DoD-approved External PKIs are Foreign, Allied, or Coalition Partner PKIs. Deploying the ALG with TLS enabled will require the installation of DoD and/or DoD-approved CA certificates in the trusted root certificate store of each proxy to be used for TLS traffic. This requirement focuses on communications protection for the application session rather than for the network packet.

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 that control the flow of network traffic (e.g., application level firewalls and Web content filters), ensure the flow of traffic is only allowed from authorized sources to authorized destinations. Networks with different levels of trust (e.g., the internet or CDS) must be kept separate.

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.

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.

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.