Practical guidance for CISOs to build enterprise-wide mobile security programs that stand up to advanced spyware and surveillance threats.
Over the past decade, smartphones have quietly become the de facto endpoint for many critical business processes. Executives approve wire transfers from their phones, deal teams negotiate from encrypted chat apps, and employees rely on mobile devices for identity verification, collaboration, and remote access. Yet in many organizations, mobile security lags far behind the rigor applied to laptops, servers, and cloud platforms.
The result is an expanding attack surface tailor-made for sophisticated spyware, metadata harvesting, and corporate espionage. The challenge is structural as much as technical. Mobile ecosystems are fragmented, with multiple operating systems, vendor-specific security baselines, and a proliferation of apps that blur the line between personal and professional use.
Bring-your-own-device (BYOD) policies, while attractive for cost and convenience, can leave security teams with limited visibility into the very endpoints that handle their most sensitive data. At the same time, adversaries ranging from criminal groups to commercial surveillance vendors and state-linked actors increasingly view mobile as the most efficient way to compromise organizations, either by installing advanced spyware or by exploiting weaknesses in the broader mobile communications ecosystem.
For CISOs and security leaders, the goal is not to eliminate mobile risk—that is neither realistic nor necessary—but to bring it under the same disciplined management as other enterprise assets. That means understanding where mobile fits into business workflows, defining risk-based policies for different user populations, and implementing layered controls that assume compromise is possible and focus on minimizing impact.
In practice, this involves choices about device ownership models, management tools, authentication standards, and user experience tradeoffs that will shape how your organization works every day. This article lays out a practical roadmap for building or maturing an enterprise mobile security program that can stand up to advanced threats without crippling productivity. Drawing on guidance from NIST and CISA and lessons from recent Pegasus-style spyware revelations, it focuses on realistic controls that enterprises can deploy today across both corporate and BYOD fleets.
Designing effective technical controls for mobile security starts with clear architectural choices. Enterprises need to decide how they will manage devices (corporate-owned, COPE, BYOD), what level of control they require, and how they will enforce minimum standards across that diversity.
For corporate fleets, a modern enterprise mobility management (EMM) platform should be non-negotiable; it provides the policy engine to configure encryption, enforce screen locks, prevent sideloading, manage app permissions, and trigger remote wipe. For BYOD environments, mobile application management (MAM) and secure containers can strike a balance between user privacy and corporate control. A layered approach should combine baseline hardening with dedicated mobile threat defense.
At the OS level, require device encryption, strong screen-lock policies, and regular patching; block jailbroken or rooted devices from accessing corporate resources. At the app level, maintain an allowlist of trusted titles for sensitive functions like messaging, conferencing, and file sharing, and use app vetting to catch insecure or overly intrusive software before it becomes standard. For executives and employees who regularly conduct highly sensitive conversations, a purpose-built secure device may be warranted beyond what standard app controls can provide. The Sotera SecurePhone is purpose-engineered for exactly this use case, offering government-certified encrypted voice and messaging on hardened hardware designed to keep confidential communications private from the ground up — not as an afterthought.
Integrating a mobile threat defense agent can provide runtime detection of malware, risky network connections, and unusual behavior indicative of compromise, complementing the pre-deployment checks. Network and identity layers are equally important. Rather than relying solely on VPNs, many organizations are converging on zero trust architectures that evaluate device posture and user context before granting access to applications. That means checking OS versions, EMM enrollment status, and mobile threat defense signals at login time and continuously thereafter.
Standards-based guidance such as NIST SP 800-124r2 and broader zero trust recommendations in NIST SP 800-207 can help security teams define the right control points. Because mobile compromises often start with human factors, technical controls should also support safer behavior by default. For example, enforce FIDO-based multi-factor authentication for high-value accounts, eliminating SMS as a second factor in line with CISA’s mobile communications best practices. Configure email and collaboration tools to warn users when messages originate from outside the organization, and route links through secure web gateways that can detect Pegasus-style phishing infrastructure. Over time, analyzing telemetry from these controls can reveal which teams or geographies face the heaviest mobile-focused targeting and where additional support is needed.
Technical architecture is only effective if the organization can operate it consistently. That’s why mature mobile security programs put equal emphasis on governance, process, and culture. Governance begins with assigning clear ownership: typically the CISO, supported by a cross-functional working group that includes legal, HR, compliance, procurement, and executive support. This group should define policies covering device eligibility, acceptable use, travel protocols, incident response, and third-party access. Processes translate those policies into repeatable actions.
Onboarding needs to ensure that new hires, executives, and contractors receive the right devices, enroll in EMM or MAM, and understand what is expected of them. Change management should cover OS and app updates, ensuring they are tested, rolled out, and, where necessary, rolled back without leaving large pockets of unpatched devices.
Incident response playbooks should be explicit about how to handle suspected mobile compromise: from initial containment steps to communication with affected individuals and, if required, regulators. Culture makes these practices sustainable. If staff view mobile policies as arbitrary obstacles, they will find ways around them; if they understand the connection between their phone habits and risks like corporate espionage or regulatory exposure, they are more likely to engage.
Use real-world examples—such as Pegasus infections of journalists and officials, or Vodafone’s explanation of how Pegasus-class spyware can silently compromise employee phones in this overview of securing employee phones—to show that the threat is both concrete and evolving.
Finally, treat mobile security as a living program. Establish metrics such as EMM enrollment coverage, time to patch critical mobile vulnerabilities, adoption of phishing-resistant MFA on mobile, and the number of detected mobile threat defense events. Report these regularly to the board alongside traditional cyber KPIs, and use them to drive continuous improvement. As toolkits targeting phones become more sophisticated and more widely available, enterprises that have already normalized strong mobile hygiene, layered defenses, and clear executive ownership will be far better positioned than those still treating phones as an afterthought.