By traditional Middle East standards the odds against Syrian President Hafez Assad appear to be lengthening ominously.

It's hardly surprising that Syrians note he's aged in recent photographs. For he's beset by a string of unsolved bomb explosions, political assassinations and other signs of public desaffection.

His army is bogged down in unpopular occupation duty in Lebanon with no end in sight. Across the southern border, where his weakened forces on the Golan Heights face Israel at peak efficiency. He is no longer dealing with the relatively accommodating Labor government. Rather, Assad as one of the key players in the Middle East conflict, desperately needs some quick movement towards peace - reasonably can expect little from pugnacious Israeli Prime Minister Menaham Begin.

The economy, afflicted with stagflation and a rigid public sector so far incapable of capitalizing quickly on potentially favorable trends, is only now showing signs of emerging from deep trouble.

Yet, for the time being even his critics believe Assad will survive nicely. They credit the 47-year-old leader's gift of careful cunning which has kept his regime, based on his once detested Alawite Moslem seet minority, for a record seven years in a country long synonymous with Middle East coups.

His handling of the current anti-corruption campaign appears to be a text book example of how to navigate intricky waters to re-establish an authoritarian regime's shaken credibility.

Like so many Assad initiatives, it looks potentially dangerous, but its every step has probably been thought out to the slighest detail.

Shocked by the boycott of the Aug. 1 and 2 National Council elections - no more than five per cent of the registered voters bothered to cast ballots - Assad got the message.

He ordered a special investigation. It is said to have conluded that public disaffection was due to his decision to aid the Christian minority during Lebanon's civil war and to the economic mess symbolized by high level corruption.

Assad himself had warned of the evils of corruption in a litany of public statements for more than a year urging sinners to correct their evil ways. His reform-minded prime minister, Gen. Abdel Rhaman Kleifawi, is said to have preached to little avail the necessity of a cleanup campaign since his appointment in August 1976.

Assad's admirers insist his time was monopolized by his Lebanese adventure and that his characteristic thoroughness was distracted from economic problems and the speculations of the powerful.

In any case, the president is the first modern Syrian leader to attempt to clean house without benefit of a coup d'etat, although critics doubt he can prosecute the guilty without endangering his regime.

For rightly or wrongly, rumors of corruption include his principal licutenants and even his brother Rifaat, the leader of the regime's pretorian guard.

But many Syrian observers are convinced that the anti-corruption campaign is really designed to allow the president to end the serious, persistent squabbling among his top followers.

The president's aplomb is testified to by the fact that the regime has continued to do business as usual - compared to the usual shuddering halt less momentous problems once caused here.

On the surface he appears to be in total control. On Aug. 6 he published a presidential decree increasing penalties for economic crimes. Two days later another decree established a special tribunal for economic crimes.

A week thereafter editorials began appearing, said to bear his personal imprint, denouncing corruption in high places. On Aug. 18 he himself spoke and a committee to investigate curruption was established.

The president himself set the tone by announcing he was handing over to the state all his real estate holdings.

In succeeding weeks 27 men are said to have been arrested - including 16 whose names are known.

Some are evil servants in positions of influence in granting government contracts, said to be the principal source of graft.

But the biggest names were those of Osman Aidi, Saeb Nahas, Abdel Rahman Attar and Nazir Hadaya. All are big businessmen, the kind of local movers and shakers and outside world has become accustomed to identify with commission agents like Saudi Arabia's Adnan Kashoggi.

In a country without a free press, these men's highly-placed protectors are nonetheless well known. A pattern emerged implicating the president's most important and often squabbling lieutenants. The Arab Press abroad has mentioned Rifaat Naji Jamil, the air force commander, deputy defense minister and coordinator of national intelligence, and Mohamed Bajbouj, deputy secretary general of the ruling regional command of the Baath Party,

So far the regime has not announced the arrest of any army officers but diplomatic sources do not discount persistent rumors that between five and ten high ranking officers involved directly or indirectly in military procurement may have been detained.

Conventional wisdom is convinced that President Assad, who keeps a close watch on the army, is not about to embarrass what remains his principal power base. Yet a persistent rumor involves a $15,000 payoff for each of 50 French-built Gazelle helicopters recently acquired by the hitherto almost entirely Soviet-equipped armed forces.

Some 100 ministers, former ministers deputy ministers directors of state companies and other high-ranking civil servants have been asked to account in writing for their financial situation over the past five years.

This week the 18 members of the regional baath command followed the president's example in announcing they were handling over all real estate holdings - except their personal homes - to the state. In the public mind the move was aimed especially at Assad's brother Rifaat, the most prominent of the command's members.

According to the cognoscenti, the president has cleverly arrested many Sunnis, the majority Moslem seet, among the businessmen. It's his way of saying to both the Alawite ruling elite and its allies among the Sunnis, the minority Christians and Shia Moslem: "We're all in this together so let's not cause trouble," an observer suggested.

The public is convinced that the president is not about to let the campaign get out of hand. Heading the investigative committee, for example, is Ahmed Diab, a man closely associated with Rifaat.

Indeed what seems most unclear is how far the president intends to go. "It's one thing to make these fat cats pay back taxes for fine them, quite something else to put them on trial," a Syrian noted "for there's always the chance they'd talk too much and after all in bribery there's not just the fellow who takes the bribe, but he who offers it."

Best bets are that a government and perhaps a Baath regional command reshuffle will be forthcoming and mark the high point in the campaign signalling that henceforth the president counts on a new team of subordinates.

So far the only negative result of the anti-corruption campaign has been the shock caused the business community.

Only in recent years have businessmen recovered from the rigors of the Baath Party's all out mid-Sixties wave of nationalizations. The arrest of some of their more prominent leaders was reflected in the flight of capital abroad which was reflected in the Syrian pound's decline from 4.01 to 4.18 on the free market.

Ironically, many of the arrested businessmen played a critical role in bailing the government out of its most embarrassing difficulty in years. Working outside the official banking system - and making fat profits in the process - the private sector was able to pay for the imports which the regime itself could not afford.

For the root cause of the regime's unpopularity lies less in corruption itself - which few Syrians complained about when the going was good - than in the economic mess of the past 18 months.

Deprived during the evil war of the port of Beirut and the Lebanese system's market economy flexibility, the rigid top-heavy government sector simply seized up.

The cost of living increased enormously, especially hurting the middle class civil servants and army officers who make up the backbone of the regime. They have had their wages fromzen for the past four years. By comparison, the poor were cushioned from the full effects of inflation by govrnment subsidies for staples.

By the end of last year the central bank was able to convince Assad of the impending disaster over the country's inability, to meet short-term debts. Projects were junkel, imports curtailed, debts payments allowed to lapse to East European creditors - but not to Western commercial banks for fear of harming Syria's credit rating - and supplier credit repayments stretched out.

Compounding Syria's problems was still mysterious Saudi Arabian failure to provide promised cash payments during the first half of this year - although as much as $300 million was forthcoming in July.

Analysts forecast that Syria will be out of the woods by the end of the year, but must continue to exercise discipline on foreign exchange.

"The regime's real Archiles heel is reforming the administration, somehow finding a way to make it responsive to the real world," a Western diplomat said, "and persuading the Baath Party to accept market forces in far from a foregone conclusion."

News agencies reported the following other Middle East developments:

Fighting subsided in southern Lebanon and Palestinian guerrillas attributed the lull to the Jewish Yom Kippur holiday. Some scattered shelling was reported and the Lebanese government complained that Israeli tanks made fresh crossings into Lebanon. Israeli authorities in Tel Aviv continued to decline comment about the reported incursions.

An explosion in the town of Nablus in the Israeli-occupied West Bank of the Jordan River killed two Arab youths and injured a third, Israeli authorities said. The three apparently were handling a bomb when it went off prematurely.