CBS Reports 'Suspicious' Cell Phone Tower Activity In Washington DC

"An unusually high amount of suspicious cell phone activity in the nation's capital has caught the attention of the Department of Homeland Security, raising concerns that U.S. officials are being monitored by a foreign entity," reports CBS News:
The issue was first reported in the Washington Free Beacon, but a source at telecom security firm ESD America confirmed the spike in suspicious activity to CBS News. ESD America, hired preemptively for a DHS pilot program this January called ESD Overwatch, first noticed suspicious activity around cell phone towers in certain parts of the capital, including near the White House. This kind of activity can indicate that someone is monitoring specific individuals or their devices... According to the ESD America source, the first such spike of activity was in D.C. but there have been others in other parts of the country. Based on the type of technology used, the source continued, it is likely that the suspicious activity was being conducted by a foreign nation.
The news coincides with a letter sent to the DHS by two congressmen "deeply concerned" about vulnerabilities in the SS7 protocol underlying U.S. cellular networks, according to an article shared by Slashdot reader Trailrunner7. Senator Ron Wyden and Representative Ted Lieu are asking if the agency
has enough resources to address the threat. "Although there have been a few news stories about this topic, we suspect that most Americans simply have no idea how easy it is for a relatively sophisticated adversary to track their movements, tap their calls, and hack their smartphones."