The employment contract is binding so long you are employed. And the contract is, in a way governed by Malaysian Employment Act. Similar to your expectation to be paid monthly as stipulated, the employer would expect you to fulfill your side of requirements. Leaving without sufficient notice is still governed by the contract, thats why you see the clause of x months notice or you have to fork out x amount of money to pay your way out. So, in this case, your employer has every right to ask for compensation from you, and in some extreme cases, bring the issue up to court/labor dept. But bear in mind that the process is very tedious. Think for yourself, you quit in short notice. Then your ex-employer send a letter asking for compensation as stipulated in the contract. If you pay, closed case. If not, your ex-employer could engage the company's or external lawyer to seek compensation. After few rounds of sending reminder letter, your ex-company could bring the issue up to the court, and court will decide how much you should pay monthly, etc ... based on your new income, etc (just like if someone defaulted a loan).

TS,

1.Employer can ask for compensation from you, by any lawful means. And suing you is one of the avenues.
2. It wont look good in your employment history, or to some extent your credit history should it goes to court (background check, past employers referral, etc).

What you should do,

1. Talk to soon to be ex-company HR for leeway, waiver or even partial payment (Seen peeps dont have to pay a single cent after nego).
2. Ask your new company to buy you out (If they really, really, really want you )
3. Pay out and move on with your life. Not so much difference timewise between 1 - 3 months:p