He also served as a general in the Lebanese army during the country's 1975-1990 civil war, but quit the military after Aoun went into exile in France.
If convicted, Karam, 64, could face the death penalty.
Ibrahim Najjar, Lebanon's justice minister, said his ministry assembled 150 cases of spying for Israel, adding that he is planning to raise the issue with the UN Security Council.
The names are "of all sects and denominations. There are some truly complex and unbelievable cases", he said.
Arrested two weeks ago, Karam's case has added to concerns in Lebanon about the ability of the Israeli intelligence to infiltrate the country.
More than 70 people have been arrested on suspicion of spying for Israel's Mossad intelligence agency since April 2009, when the government launched a nationwide crackdown on suspected agents.
The arrests include members of the security forces and telecom employees.
Michel Sleiman, Lebanon's president, who under Lebanese law must sign a death sentence before it is carried out, has called for severe punishment for spies.
The cabinet also agreed that death sentences handed down to spies for Israel should be carried out.
Three men have since been sentenced to death, including one found guilty of aiding Israel during its devastating 2006 war with Hezbollah.