Advisories MDKSA-2007:080: Updated tightvnc packages fix integer overflow vulnerabilities

[paul]

Local exploitation of a memory corruption vulnerability in the X.Org

and XFree86 X server could allow an attacker to execute arbitrary code

with privileges of the X server, typically root.

 

The vulnerability exists in the ProcXCMiscGetXIDList() function in the

XC-MISC extension. This request is used to determine what resource IDs

are available for use. This function contains two vulnerabilities,

both result in memory corruption of either the stack or heap. The

ALLOCATE_LOCAL() macro used by this function allocates memory on the

stack using alloca() on systems where alloca() is present, or using

the heap otherwise. The handler function takes a user provided value,

multiplies it, and then passes it to the above macro. This results in

both an integer overflow vulnerability, and an alloca() stack pointer

shifting vulnerability. Both can be exploited to execute arbitrary

code. (CVE-2007-1003)

 

iDefense reported two integer overflows in the way X.org handled

various font files. A malicious local user could exploit these issues

to potentially execute arbitrary code with the privileges of the X.org

server. (CVE-2007-1351, CVE-2007-1352)

 

TightVNC uses some of the same code base as Xorg, and has the same

vulnerable code.

 

Updated packages are patched to address these issues.