Hidden Risks in Carrier Billing: How Mobile Payment Systems Enable Fraud

The convenience of carrier billing systems in mobile devices has become a double-edged sword, creating unexpected vulnerabilities in payment security. Recent investigations uncover how threat actors are exploiting these systems to perpetrate subscription scams and unauthorized charges at scale.

The Anatomy of Carrier Billing Vulnerabilities

Modern smartphones integrate carrier billing at multiple levels - from app stores to physical device functions. Our research identified three primary attack vectors:

1. Power Button Exploits: Certain Android devices allow payment authorization through power button sequences, a feature often unknown to users. Attackers can manipulate these hidden functions via malware or social engineering.

1. Opaque Charge Mechanisms: Carrier billing systems frequently lack transparent confirmation steps, allowing fraudulent charges to blend with legitimate carrier fees. The Samsung Galaxy A15 case revealed how attackers leverage mid-range devices with carrier billing enabled by default.

1. Subscription Fraud Loopholes: Apple's ecosystem, while generally more secure, shows vulnerabilities in cross-service subscriptions like Apple One, where carrier billing can bypass some App Store security checks.

Technical Deep Dive

The security flaws stem from three core issues in implementation:

• Insufficient Authentication: Many carrier billing systems rely solely on device possession as authentication, without secondary verification
• Poor Charge Visibility: Charges often appear under vague descriptions in carrier statements
• Silent Renewals: Subscription services frequently auto-renew through carrier billing without adequate user notification

Enterprise Impact and Mitigation Strategies

For security professionals, these vulnerabilities present significant challenges:

• Fraud Detection: Traditional payment fraud systems often miss carrier billing anomalies
• Device Management: Enterprises must update mobile device policies to account for these risks
• User Education: Employees using corporate devices need awareness of these threats

Recommended mitigation measures include:

1. Implementing carrier billing monitoring solutions
2. Disabling premium SMS and direct carrier billing on enterprise devices
3. Requiring secondary authentication for all carrier-charged services

As mobile payments continue evolving, security teams must prioritize these often-overlooked attack surfaces in their threat models.