Incumbent Connecticut Democratic Gov. Dannel P. Malloy and challengers Tom Foley and Joe Visconti. Jessica Hill/Associated Press

A new poll showing a tie between the major-party candidates in Connecticut’s gubernatorial race suggests that Democratic Gov. Dannel Malloy ’s attacks on his Republican challenger are working, political analysts said.

Both Mr. Malloy and Tom Foley earned 43% support, according to the Quinnipiac University survey of likely voters. Mr. Malloy erased a six-percentage-point deficit from the last Quinnipiac poll in September. Mr. Malloy narrowly edged Mr. Foley in the 2010 election for governor.

The poll also showed an increase in the number of independent voters who said they had an unfavorable opinion of Mr. Foley, said Scott McLean, professor of political science at Quinnipiac University.

“It means the Malloy campaign’s [strategy of] taking the more negative side of things is starting to pay off,” Mr. McLean said.

For Mr. Foley, wooing unaffiliated voters will be vital in a state where registered Democratic voters outnumber Republicans 798,000 to 437,000.

“We are going to continue to work as hard as possible every day between now and when the polls close on Nov. 4,” said Chris Cooper, a spokesman for Mr. Foley

The Malloy campaign declined to say much about the poll. “Polls go up and down,” said Mark Bergman, senior adviser for Mr. Malloy’s campaign. “Gov. Malloy has always been focused on doing the right thing for Connecticut families.”

Political observers said the race was likely to remain tight. In 2010, Mr. Malloy won by about 6,400 votes out of 1.146 million cast. Conservative candidate Thomas Marsh received about 17,600 votes.

Along with outside groups that support Mr. Malloy, his campaign has aired negative television ads depicting Mr. Foley as a callous businessman who can’t identify with middle-class citizens.

“Those ads are really targeting that he doesn’t care about workers,” said William Salka, chairman of the political science department at Eastern Connecticut State University. “As voters get more exposure to him…that is what is leading to these negative attitudes.”

On Wednesday, the Malloy campaign released an ad called “Yacht.”

“The world must look different from a $5 million yacht,” a narrator said on the television spot while showing what appears to be Mr. Foley’s boat. The ad warns that if Mr. Foley is elected, he would view his job from the helm of a yacht.

Mr. Foley has tried to counter the negative ads by featuring his wife and children in some of his own videos. But his campaign has also used a number of negative ads attacking Mr. Malloy.

In an ad released in September titled “What’s the Plan,” a narrator criticizes Mr. Malloy’s economic policies and says they are driving residents out of the state. The narrator tells viewers that Mr. Malloy will raise taxes if he is re-elected, which Mr. Malloy has said he wouldn’t do. In 2011, Mr. Malloy signed off on a plan to raise taxes by $1.5 billion to help close a $3.6 billion deficit.

The Quinnipiac University poll also included this year’s wild-card candidate—conservative independent Joe Visconti, who drew 9% support. When the results are recalculated without Mr. Visconti, Mr. Malloy and Mr. Foley remained tied, with 46% for each candidate.

Jeff Weiss, a spokesman for Mr. Visconti, said he would have gained more support if he hadn’t been excluded from the previous gubernatorial debates.

The poll also showed that 41% of the likely voters in the survey had favorable opinions of Messrs. Foley and Malloy.

“The voters are not wild about either candidate right now,” said Douglas Schwartz, director of the Quinnipiac University poll.

Write to Joseph De Avila at