[dbsec] Oracle RDBMS TNS Data packet DoS

  • From: "NGSSoftware Insight Security Research" <nisr@xxxxxxxxxxxxxxx>
  • To: <bugtraq@xxxxxxxxxxxxxxxxx>, <full-disclosure@xxxxxxxxxxxxxxxxx>, <dbsec@xxxxxxxxxxxxx>
  • Date: Wed, 17 Oct 2007 12:55:55 +0100

NGSSoftware Insight Security Research Advisory

Name: Oracle RDBMS Data packet DoS
Systems Affected: Oracle, 10g Release 2 and 1, Oracle 9
Severity: High
Vendor URL: http://www.oracle.com/
Author: David Litchfield [ davidl@xxxxxxxxxxxxxxx ]
Reported: 23rd June 2006
Date of Public Advisory: 17th October 2007
Advisory number: #NISR17102007D

The Oracle RDBMS on receiving an invalid TNS data packet will use 100% of
the CPU's time introducing a Denial of Service condition.
Once a client connects to the database process and performs protocol
negoation (TNS packet type 1) and data type represenations (packet type 2)
it may then  send packets of type 6 - Data packets. If the server gets a
packet with the 2nd bit of the Data flags is set then the server runs at
100% CPU:

"\x00\x1D" // Packet Size
"\x00\x00" // Packet Checksum
"\x06" // Packet Type [DATA]
"\x00" // Flags
"\x00\x00" // Header Checksum
"\x00\x02" // Data flags
"\x03\x3B" // TTI Version function

The snippet of a packet above sets the Data flags to 0x0002 on a version
request. This DoS condition can be triggered prior to authentication. This
can be exploited by an unauthenticated attacker.

Fix Information
Oracle was alerted to this flaw on the 23rd of June 2006. A patch has now
been made available:


NGSSQuirreL for Oracle, an advanced vulnerability assessment scanner
designed specifically for Oracle, can be used to accurately determine
whether your  servers is vulnerable to this flaw. More information about
NGSSQuirreL for Oracle can be found here:


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  • » [dbsec] Oracle RDBMS TNS Data packet DoS