Symantec’s semi-annual Internet Security Threat Report is out, covering the first half of 2007. The thorough and useful report unfortunately suffers from a severe case of TMI: too much information. Weighing in at 132 pages, including 22 pages of appendices, the report will take quite a while to fully digest. Here’s a quick overview for now:

Executive summary: the executive summary is so long it actually has a summary itself. The summary summary highlights attack, vulnerability and malicious code trends, as well as phishing and spam issues. Each of these items is called out in a detailed section later in the report. For most of us, just reading the executive summary (20 pages) should be more than sufficient.

Future Watch: this section, and the appendices are the only ones not mentioned in the executive summary. The most interesting part of this section is entitled “Malicious code and virtual worlds,” and addresses potential security issues in environments like Second Life and World of Warcraft.

Attack Trends: a massive amount of information of questionable accuracy. Very interesting if at all true however. The key claim may be that 95% of all attacks are against home users. Another interesting claim is that 4% of all malicious activity originated from within Fortune 500 companies. The U.S. is by far the most targeted, although it only originates 25% of the attacks. Amazingly, Symantec observed over 50,000 active bot-infected computers per day!

Vulnerability Trends: of the nearly 2500 vulnerabilities Symantec documented, over 60% were in Web applications. 25 of these were in Safari, a surprisingly large number given that only 39 were in Internet Explorer. But Safari had the lowest “average window of exposure,” only 3 days. There were over 200 Web plug-in vulnerabilities, almost all of which were in ActiveX plug-ins (which don’t run under OS X). But there were 18 vulnerabilities in QuickTime plug-ins.

Malicious Code Trends: precisely 212,101 new malicious code threats were reported over the first half of 2007, nearly triple the number reported in the second half of 2006. Many of these were Trojans and included keystroke loggers. Half were spread by SMTP (email).

Phishing: precisely 196,860 unique phishing messages were detected (only an 18% increase). Keep in mind than many phishing messages are slight variants of each other however. Almost half of all messages came from three “phishing toolkits” (a worrisome class of software). Almost 60% of all phishing Web sites were located in the U.S., a surprisingly high number.

Spam: about 60% of all email traffic was spam (this figure seems low compared to other claims) and only 60% of the spam was in English. Almost 50% of spam originated in the U.S., with the most likely explanation being the high number of bot-infected computers here. One-quarter of all spam was image spam.

Appendices: the only really interesting appendix is the two page one on “best practices,” which is broken down into Enterprise and Consumer sections. Definitely worth a read, but keep in mind the source.