There has been no official announcement of any changes, which is normal for the security-obsessed regime whose inner workings have long been opaque and little-known.
But the reports come amid a widening crisis in the Middle East and U.S. efforts to lure Syria away from its 30-year-old strategic alliance with Iran.
The U.S. global security consultancy Stratfor says the shuffle took place in September and was extensive. It said that the commander of air force intelligence, Maj. Gen. Abdulfattah Qudsiya, was transferred to head Military Intelligence, the principal service among Syria's myriad security agencies. Qudsiya was replaced by Brig. Gen. Jamil Hassan, deputy head of State Security, who was promoted to major general.
Maj. Gen. Zuhair Hamad, a counter-terrorism specialist, was promoted from head of the Special Intelligence Unit at State Security to become chief of the entire department, with Brig. Gen. Ghassan Khalil as his deputy. Hamad replaced Maj. Gen. Ali Mamluk, who has reached the mandatory retirement age of 62.
Mamluk, who has run State Security since 2004 and has been involved in some of the most sensitive issues concerning Syria, will become a special adviser on security to Assad, joining Maj. Gen. Mohammed Nassif, who is close to the president.
Stratfor said that the head of Military Intelligence, Maj. Gen. Assef Shawkat, Assad's brother-in-law, was promoted to lieutenant general "in preparation for appointing him minister of defense."
Intelligence Online, a Paris Web site, also reported Mamluk's new appointment but said that Shawkat was sidelined by Assad in 2008 and remains in disgrace. The status of Shawkat, who is married to Assad's strong-willed sister Bushra, in the Syrian hierarchy has been unclear for some time.
Two years ago he was reported to have been shunted aside because of deep differences with Assad's brother, Maher, who commands the elite Presidential Guard.
The marriage of Shawkat, seen by many in the regime as ambitious and hungry for power, to Bushra was opposed by Hafez Assad and others in the family. However, Shawkat was reported to have been appointed chief of military intelligence, the most powerful of Syria's security services, Feb. 18, 2005.
The conflicting reports on his status only add to the confusion about what is happening in the upper echelons on the regime's security and intelligence establishment.
Assad periodically shuffles commands in this apparatus as a matter of course, presumably to prevent senior officers establishing centers of power that might threaten the presidency.
But the reports of a reshuffle in recent weeks come amid a backdrop of significant events in the region that could decide whether there will new conflicts or geopolitical realignments, most of them involving Syria.
"This reshuffle takes place at a time when the Syrian regime is taking a number of calculated foreign policy risks with the intent of expanding Syria's influence in the region," Stratfor observed.
"While keeping an eye on the U.S.-Iran negotiating track, Syria is -- in collaboration with the Saudi government -- using its dominant position in Lebanon to contain Hezbollah."
Stratfor, along with other U.S. observers, has been pointing to differences between Syria, Iran's ally, and Hezbollah, Iran's main surrogate in the Middle East.
Arab commentators are less inclined to that assessment. But as Syria steadily restores its control over Lebanon, five years after a military withdrawal triggered by the 2005 assassination of former Lebanese Prime Minister Rafik Hariri, there are those who believe Damascus will have to rein in longtime ally Hezbollah to re-impose its mastery.
Syria's July rapprochement with Saudi Arabia, Iran's main Arab rival, in an apparent effort to prevent Lebanon erupting in sectarian violence again was seen by some as a rebuff for Tehran.
However, Assad visited Tehran Oct. 2 and declared the alliance was as strong as ever.
Stratfor viewed Hamad's takeover of State Security as "the most intriguing" aspect of the reshuffle.
Hamad, it said, is close to the Iranians "and Tehran made it clear it wanted Hamad to replace Mamluk," who was seen as the architect of the July agreement between Damascus and Riyadh "that focused on controlling Hezbollah's actions in Lebanon."