The "Bolstering Security Against Ghost Guns Act" amends the Homeland Security Act of 2002 to significantly enhance the Department of Homeland Security's efforts against threats posed by ghost guns. Within one year, the Secretary, through the Under Secretary for Strategy, Policy, and Plans, must issue a Department-wide strategy to improve prevention, preparedness, and response to homeland security threats, such as terrorism or targeted violence, associated with these firearms. This strategy will identify activities across DHS components and foster collaboration with Federal, State, local, Tribal, and territorial partners. The bill mandates several specific actions from various DHS agencies. The Under Secretary for Intelligence and Analysis, in coordination with U.S. Customs and Border Protection and U.S. Immigration and Customs Enforcement, must develop a homeland security threat assessment within 180 days focusing on cross-border threats from U.S.-sourced ghost guns, particularly those used by transnational criminal organizations. Additionally, the Director of the United States Secret Service is directed to conduct research and issue public reports providing guidance on preventing and responding to ghost gun-related threats. Furthermore, the Transportation Security Administration Administrator is required to report annually on violations involving unauthorized firearm carriage at passenger screening checkpoints, including incidents with ghost guns and repeat offenses. U.S. Immigration and Customs Enforcement must analyze data on U.S.-sourced firearms, including ghost guns, recovered in Mexico, develop mechanisms for information sharing, and establish performance measures for combating illicit cross-border activities. Finally, the Office of Intelligence and Analysis will produce annual reports assessing ghost gun threats associated with foreign terrorist organizations or acts of terrorism, disseminating these findings to law enforcement and Congress.