BKINSIAN.RVW   20030831

"Intrusion Signatures and Analysis", Stephen Northcutt et al, 2001,
0-7357-1063-5, U$39.99/C$59.95/UK#30.99
%A   Stephen Northcutt stephen@sans.org
%A   Mark Cooper
%A   Matt Fearnow
%A   Karen Frederick
%C   201 W. 103rd Street, Indianapolis, IN   46290
%D   2001
%G   0-7357-1063-5
%I   Macmillan Computer Publishing (MCP)
%O   U$39.99/C$59.95/UK#30.99 800-858-7674 info@mcp.com
%O  http://www.amazon.com/exec/obidos/ASIN/0735710635/robsladesinterne
  http://www.amazon.co.uk/exec/obidos/ASIN/0735710635/robsladesinte-21
%O   http://www.amazon.ca/exec/obidos/ASIN/0735710635/robsladesin03-20
%P   408 p.
%T   "Intrusion Signatures and Analysis"

Intrusion detection and network forensics are now vitally important
topics in the security arena.  An explanation of how to identify
dangerous signatures, and extract evidence of an intrusion or attack
from network logs, is something that most network administrators
require.  Unfortunately, while the idea is good, and badly needed, the
execution, in the case of the current work, is seriously flawed.

The introduction doesn't really specify a purpose or audience for this
book.  Mention is made of the GIAC (Global Incident Analysis Center,
also seemingly referred to at times as the GCIA) certification, but no
definition is given as to what this actually is.  Chapter one presents
a number of examples of network log entries and formats.  The
interpretation, though, concentrates on easily identifiable items such
as IP addresses, and neglects components that are less well known. 
There seems to be some attempt to structure the descriptions, but it
is unclear and confusing, as are a number of the illustrations and
figures.

Chapters three and four list a "top ten" of specific attacks,
described down to a byte level, but not always in clear detail. 
Perimeter logs, such as those from firewalls and routers, are
discussed in chapter six.  Restraint in reaction to odd traffic is
urged in chapter seven, particularly in light of the probability of
address spoofing.  Chapter eight outlines packets that indicate
mapping scans, while nine does the same with searches that might be
gathering system information.  Denial of services attacks are reviewed
in chapters ten and eleven, first with respect to attacks that attempt
to exhaust specific resources, and then in regard to bandwidth
consumption.  Chapter twelve discusses trojan programs, concentrating
on detection of unusual open ports.  Miscellaneous exploits are listed
in chapter thirteen, but since exploits are listed throughout the
previous three chapters it is difficult to find a distinctive for this
section.  Fragmentation attacks are described in chapter fifteen. 
Chapter sixteen reports on some odd looking non-malicious packets, in
warning against reacting to false positives.  A grab bag of odd
packets is listed in chapter seventeen.

As should be evident from the description above, there is a good deal
of valuable material in this book.  Unfortunately, it is not easy to
extract the useful bits.  The book as a whole could use serious
reorganization.  While chapter one appears to be an introduction to
the technical details, a far better explanation of packets and the
import of various fields is given in chapter five, ostensibly on non-
malicious or normal traffic, and this material should probably have
been placed at the beginning of the manual.  Chapter fourteen, almost
at the end of the text, reviews buffer overflows, which are seen
throughout the chapters preceding it.  There is a slight attempt to
explain the book in chapter two, but the content and organization is
perplexing, there is heavy use of unilluminated insider jargon, and
the presentation of example packets and subsequent conclusions without
the middle step of identifying the items that make these data
suspicious could be quite frustrating to the student.  The new system
administrator will not find the explanations clear or illuminating. 
The experienced professional will not find particular attacks or
traffic types easy to find for reference.  Both groups will find
themselves flipping back and forth between sections of the book, or
even between sections of the exegesis of one particular attack.

However, both groups will likely be interested in the book anyway,
simply because of the lack of other sources.

copyright Robert M. Slade, 2003   BKINSIAN.RVW   20030831