Cybersecurity executives, engineers, and decision-makers should not presume effective network steganographic countermeasures come at the cost of performance. A performance assessment of network steganographic countermeasures during an experimental data exfiltration attack revealed a negligible influence on latency. Despite the advanced nature of the attack, preventative controls did not degrade packet round-trip times to a statistically significant degree. During the experiment, synthetic credit card numbers were exfiltrated at a rate equivalent to (US)$74,702 per second. The measured round trip time between a covert transmitting host and covert receiving host was nearly identical regardless of whether interventions were active or inactive. The de minimis effect suggests similar preventative controls in an enterprise environment would not have an adverse effect on large volumes of business network traffic in the presence of an actual attack.