SIGweaver

Enea Identifies SilentAir Espionage Group Compromising Asian Telecom Networks to Intercept SMS 2FA Codes

Enea has uncovered a sophisticated espionage operation attributed to the SilentAir group, which compromised equipment inside mobile operators across at least six Asian countries. The attackers used SS7 and Diameter signaling protocols over the IPX network to send fraudulent UpdateLocation messages, diverting calls and texts of selected targets, primarily in Taiwan. Interception accounted for 18.3 percent of observed activity, far exceeding typical surveillance operations, and included real-time capture of two-factor authentication codes. SilentAir also generated large volumes of silent SMS messages to verify diversions and maintain persistence, with activity patterns aligning to China Standard Time working hours. While Enea assesses the actor as state-sponsored with high confidence, links to China remain low-confidence, and possible ties to Liminal Panda or the SCTPE/SIGweaver tool are unconfirmed. The company has notified affected operators and recommends deploying integrated GTP, SS7, and Diameter firewalls along with treating the entire IPX as untrusted.