Disable entity expansion (instance security hardening)

If customizations do not require entity expansion, use the glide.stax.allow_entity_resolution property to completely disable external entity expansion. The XML completes parsing but doesn't include any internal or external entities.

• If you set this property to true, all external entities attempt to resolve or expand subject entities, subject to the setting of the glide.stax.whitelist_enabled property.
• If you set that property to false, all entity resolution and expansion is blocked. To learn more, see XMLdoc2 entity validation with allow list.

Prerequisites

Before setting this property:

• Set the glide.xml.entity.whitelist.enabled and glide.stax.whitelist_enabled properties to true. To learn more, see XMLdoc/XMLUtil entity validation with allow list and XMLdoc2 entity validation with allow list.
• Define a listing of comma-delimited FQDN in the glide.xml.entity.whitelist property, which is the only URLs that can be reached using XML Entity processing. property. To learn more, see XML external entity processing - allow list.

More information

Attribute	Description
Property name	glide.stax.allow_entity_resolution
Configuration type	System Properties (/sys_properties_list.do)
Configure in Instance Security Center	Yes
Purpose	This remediation control must be enabled to defend against an XML Entity Expansion/Billion Laugh attack.
Recommended value	false
Functional Impact	If the customization is using entity expansion, then, the ServiceNow AI Platform might block further processing.
Security risk	(High) An attacker can use this vulnerability to expand data exponentially, quickly consuming all system resources.
Workaround	If the customization requires entity expansion, set this property to true and follow the steps documented in XMLdoc2 entity validation with allow list.

To learn more about adding or creating a system property, see Add a system property.

For more information about OWASp resources, see OWASp.