How Liberty Costa Rica Eliminated 99% of SMS Spam in Only 3 Weeks

Business Impact

• 99% reduction in SMS spam within weeks of deploying Enea’s Adaptive Messaging Firewall, dramatically improving subscriber experience.
• Rapid deployment (within 6 weeks) and tuning leveraging Enea’s regional messaging spam expertise and proven track record.
• Immediate compliance support helped Liberty meet urgent regulatory requirements and reduce the risk of fines.

Introduction

Liberty, the largest mobile network operator in Costa Rica, faced a growing challenge that threatened both subscriber trust and regulatory compliance: a surge in SMS spam. Like other operators in the region, Liberty saw an increase in complaints about spam messages—banking scams, delivery scams, giveaway schemes, and a steady flow of gambling promotions. There were also signs that Liberty’s network was used to send spam to US networks, incurring additional costs.

Behind the scenes, the company was keenly aware that regulators across the region had begun taking a tougher stance on messaging abuse. The threat of fines was real, and Liberty aimed to address the issue proactively before it escalated.

It was obvious that Liberty needed a reliable way to protect subscribers and stay ahead of tightening regulatory expectations, and that it needed to be implemented quickly.

A Proven Solution Delivering Timely Compliance and Trusted Protection

What set this project apart was the urgent need to get it operational, combined with the expectation that it would produce immediate, credible results in a fast-evolving environment. Enea provided exactly what Liberty needed: a mature, field-proven messaging firewall capable of operating at scale from day one, supported by a dedicated messaging threat intelligence team that continuously analyzes emerging spam patterns and adjusts protections in real-time. This technical strength was reinforced by extensive regional experience as the leading messaging security provider in Latin America and a highly skilled project delivery team with a proven record of deploying complex security solutions under tight deadlines. Altogether, these assets allowed Liberty to deploy quickly without sacrificing effectiveness or operational stability.

A flexible OPEX commercial model aligned well with Liberty operating framework, enabling the commercial discussions to be quickly resolved.

Deployment took only 6 weeks from project start to the firewall’s activation in the production environment. This was made possible by Liberty’s and Enea’s flexibility, all aimed at meeting tight deadlines, resulting in a lean, fast, and pragmatic project.

One key factor that reduced delivery time was that the Adaptive Messaging Firewall already had a comprehensive set of rules ready for immediate use. It supported Liberty with proactive compliance and provided the extensive reporting required by the regulatory authority, Sutel. Additionally, Enea’s experience from neighboring countries and the North American market, which was the target for much of the spam, shortened the time needed to understand local patterns and allowed Enea to quickly block the most common fraud types, such as banking scams, delivery schemes, and giveaway schemes.

A careful tuning process followed the deployment into live traffic, where Enea worked closely with Liberty to maintain an important balance: identify and block as much spam as possible without creating false positives. Enea’s threat intelligence unit quickly identified senders, spammers, and sending patterns, allowing filters to be refined. This is an iterative process, as spammers quickly adapted after messages were blocked.

Understanding Spam in Liberty’s Services and Adding Prevention

As the firewall went live, several notable behavioral patterns appeared. Enea quickly confirmed that large amounts of spam, mainly gambling spam, originated from Liberty’s network but were terminated in US operator networks. What was unique in this case was that the spam was actually being sent from Liberty’s roaming number range, likely as a tactic to avoid detection. However, it was unsuccessful since Enea’s threat intelligence team could detect and control the messages.

This wasn’t the only tactic used by gambling spammers to avoid detection or bypass filters. For example, they often changed their URLs, registering new domains in bulk. Each domain was used for short bursts, about 200 messages, before switching to another obscure, disposable domain like silhn.info, fqzbc.cc, or kcghb.info. In the first few weeks after deployment, over 30,000 scam domains were identified and blocked.

Complaints Drop as Spammers Fail to Get Through

Perhaps the most telling sign of success was how quickly the adversaries stopped once Enea’s messaging firewall reliably began blocking their messages. Gambling spam dropped from an average of over 3,100 daily attempts in the first week to just over 300 in the second week, then down to only 16 in the third week.

Figure 1: The decline in scam messages sent over Liberty Costa Rica’s network during the first three weeks of filtering. The average per week dropped from over 3,100 daily attempts to 16 in the third week.

Within weeks of activation, overall spam volume collapsed. Complaints from subscribers dropped by approximately 99%, and the network experienced an immediate improvement in traffic hygiene. It became clear that the spammers had realized their messages no longer reached their targets and were probably moving on to less protected networks.

Osvaldo Aldao is the Chief Technology and Product Officer at Enea. According to him, operators in Latin America have begun to prioritize messaging security: “Operators across Latin America are facing increasing regulatory and fraud pressure. Liberty’s results demonstrate that fast deployment and intelligence-driven filtering can dramatically reduce abuse within weeks.”

For Liberty, the outcome was exactly what they needed: a swift deployment of a reliable messaging firewall that ensured compliance, boosted customer trust, and delivered measurable results almost immediately. Their team valued not just the technology but also the agility: being able to collaborate effectively, adapt quickly, and make decisions that kept the project efficient while ensuring long-term stability.

In the end, it was a mix of speed, flexibility, technical knowledge, and a shared dedication to results that made the project so successful. And for Liberty, the change was clear: from a growing spam problem with regulatory concerns to one of the cleanest messaging environments in their region, all within just a few weeks.