Bugs in Sun Microsystems's StarOffice and OpenOffice.org's OpenOffice application suites allow attackers to snatch control of a computer by serving up malicious documents or URLs, the two organizations said Monday.

The flaws are in StarOffice's StarCalc spreadsheet and in how the suite handles URLs, said Sun in two advisories posted to its Web site. Neither vulnerability has been patched, and Sun had no workaround or temporary defense recommendations. Nor could Sun immediately provide a patch delivery date.

The company did offer descriptions of both bugs, however. "A security vulnerability with the way StarOffice/StarSuite versions 6, 7 and 8 process StarCalc 1.0 documents (.sdc) may allow a remote unprivileged user (who provides a StarCalc document that is opened by a local user) the ability to execute arbitrary commands on the system with the privileges of the user running StarOffice/StarSuite," the first vulnerability alert said.

"A security vulnerability with the way StarOffice/StarSuite 6, 7 and 8 process hyperlinks (URLs) in documents may allow a remote unprivileged user who provides a StarOffice/StarSuite document that is opened by a local user the ability to execute arbitrary commands on the system with the privileges of the user running StarOffice/StarSuite," said an advisory regarding the second bug.

Both vulnerabilities were tagged as "highly critical" by Danish bug tracker Secunia.

The bugs were also acknowledged Monday by OpenOffice.org, the open-source organization that produces the same-name free application suite that shares a code base with Sun's StarOffice. "Several security vulnerabilities have been reported on in the media in the last week, where users' PCs could be open to attack if they opened certain documents or Web sites," the group said on home page of its site. No fixes are available for current production versions of OpenOffice.org, but the latest release candidate (RC) of v. 2.2 includes patches.

"If you have a reason to believe that your usage of OpenOffice.org puts you at risk from the new vulnerabilities, please download and use the RC now," the statement said.

OpenOffice.org 2.2 RC4 can be downloaded.

Document vulnerabilities have become popular in hacker circles. Bugs in Microsoft's Office suite, for example, have been used in several targeted attacks in the last year. The most recent Microsoft-issued security update patched six flaws in Word, and other vulonerabilities in Excel and PowerPoint, Office's spreadsheet and presentation maker, respectively.