Zone Labs ZoneAlarm provides personal firewall protection. More
information is available from:
Local exploitation of an invalid pointer dereference vulnerability in
Zone Labs LLC's ZoneAlarm personal firewall allows attackers to trigger
a denial of service (DoS) condition.
ZoneAlarm offers process specific protection by hooking the kernel API
routine NtConnectPort(). NtConnectPort() is used by programs to
implement advanced inter-process communication (IPC). The
NtConnectPort() function is declared as follows:
OUT PHANDLE ClientPortHandle,
IN PUNICODE_STRING ServerPortName,
IN PSECURITY_QUALITY_OF_SERVICE SecurityQos,
IN OUT PLPC_SECTION_OWNER_MEMORY ClientSharedMemory OPTIONAL,
OUT PLPC_SECTION_MEMORY ServerSharedMemory OPTIONAL,
OUT PULONG MaximumMessageLength OPTIONAL,
IN OUT PVOID ConnectionInfo OPTIONAL,
IN OUT PULONG ConnectionInfoLength OPTIONAL);
The problem specifically exists within vsdatant.sys as ZoneAlarm fails
to verify the second argument. 'ServerPortName' is a valid address
prior to derefencing it as a pointer. The vulnerable section of code is
0001EE93 mov esi, [esp+108h+ServerPortName]
0001EE9A mov edi, eax
0001EE9C test esi, esi
0001EE9E jz short loc_1EEB6
0001EEA0 mov edx, [esi+4]
The argument 'ServerPortName' is stored in the register ESI. A check is
made to ensure that the value is not NULL. If that check is passed, the
value is dereferenced as a pointer. Any non-zero invalid memory address
can be passed as the second argument to NtConnectPort(), resulting in a
Exploitation allows local and remote attackers who have exploited
another vulnerability to trigger a DoS in kernel space, resulting in a
"blue screen of death."
iDEFENSE has confirmed the existence of this vulnerability in ZoneAlarm
version 5.1. It is suspected that previous versions of ZoneAlarm are
vulnerable as well.
iDEFENSE is currently unaware of any workarounds for this issue.
A vendor advisory for this issue is available at:
The Common Vulnerabilities and Exposures (CVE) project has assigned the
names CAN-2005-0114 to these issues. This is a candidate for inclusion
in the CVE list (http://cve.mitre.org), which standardizes names for
01/06/2005 Initial vendor notification
01/07/2005 Initial vendor response
02/11/2005 Coordinated public disclosure
iDEFENSE Labs is credited with this discovery.
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Copyright © 2005 Verisign, Inc.
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