Code Red (computer worm)
|Common name||Code Red|
|Technical name||CRv1 and CRv2|
|Type||Server Jamming Worm|
|Isolation||13 July 2001|
The Code Red worm was first discovered and researched by eEye Digital Security employees Marc Maiffret and Ryan Permeh. They named it "Code Red" because Code Red Mountain Dew was what they were drinking at the time.
Although the worm had been released on July 13, the largest group of infected computers was seen on July 19, 2001. On this day, the number of infected hosts reached 359,000.
How it worked 
Exploited vulnerability 
The worm exploited a vulnerability in the indexing software distributed with IIS, described in Microsoft Security Bulletin MS01-033, for which a patch had been available a month earlier.
The worm spread itself using a common type of vulnerability known as a buffer overflow. It did this by using a long string of the repeated character 'N' to overflow a buffer, allowing the worm to execute arbitrary code and infect the machine. Kenneth D. Eichman was the first to discover how to block it, and was invited to the White House for his discovery.
Worm payload 
The payload of the worm included:
- defacing the affected web site to display:
HELLO! Welcome to http://www.worm.com! Hacked By Chinese!
- Other activities based on day of the month:
When scanning for vulnerable machines, the worm did not test to see if the server running on a remote machine was running a vulnerable version of IIS, or even to see if it were running IIS at all. Apache access logs from this time frequently had entries such as these:
GET /default.ida?NNNNNNNNNNNNNNNNNNNNNNNNN NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN NNNNNNNNNNNNNNNNNNN %u9090%u6858%ucbd3%u7801%u9090%u6858%ucbd3%u7801 %u9090%u6858%ucbd3%u7801%u9090%u9090%u8190%u00c3 %u0003%u8b00%u531b%u53ff%u0078%u0000%u00=a HTTP/1.0
The worm's payload is the string following the last 'N'. Due to a buffer overflow, a vulnerable host interprets this string as computer instructions, propagating the worm.
Similar worms 
On August 4, 2001 Code Red II appeared. Code Red II is a variant of the original Code Red worm. Although it uses the same injection vector it has a completely different payload. It pseudo-randomly chose targets on the same or different subnets as the infected machines according to a fixed probability distribution, favoring targets on its own subnet more often than not. Additionally, it used the pattern of repeating 'X' characters instead of 'N' characters to overflow the buffer.
See also 
- ANALYSIS: .ida "Code Red" Worm, Code Red advisory, eEye Digital Security, 17 July 2001
- Moore, David; Colleen Shannon (2001?). "The Spread of the Code-Red Worm (CRv2)". CAIDA Analysis. Retrieved 2006-10-03.
- MS01-033 "Microsoft Security Bulletin MS01-033: Unchecked Buffer in Index Server ISAPI Extension Could Enable Web Server Compromise", Microsoft Corporation, 18 June 2001
- Lemos, Rob. "Virulent worm calls into doubt our ability to protect the Net". Tracking Code Red. CNET News. Retrieved 14 March 2011.
- "CERT Advisory CA-2001-19: 'Code Red' Worm Exploiting Buffer Overflow In IIS Indexing Service DLL". CERT/CC. 17 July 2001. Retrieved 2010-06-29.
- Code Red II analysis, Steve Friedl's Unixwiz.net, last update 22 August 2001
- CAIDA Analysis of Code-Red, Cooperative Association for Internet Data Analysis (CAIDA) at the San Diego Supercomputer Center (SDSC), updated November 2008
- Animation showing the spread of the Code Red worm on 19 July 2001, by Jeff Brown, UCSD, and David Moore, CAIDA at SDSC