EICAR test file

The EICAR Standard Anti-Virus Test File or EICAR test file is a computer file that was developed by the European Institute for Computer Antivirus Research (EICAR) and Computer Antivirus Research Organization (CARO), to test the response of computer antivirus (AV) programs. Instead of using real malware, which could do real damage, this test file allows people to test anti-virus software without having to use a real computer virus.

Anti-virus programmers set the EICAR string as a verified virus, similar to other identified signatures. A compliant virus scanner, when detecting the file, will respond in exactly the same manner as if it found a harmful virus. Not all virus scanners are compliant, and may not detect the file even when they are correctly configured.

The use of the EICAR test string can be more versatile than straightforward detection: a file containing the EICAR test string can be compressed or archived, and then the antivirus software can be run to see whether it can detect the test string in the compressed file.

Design

The file is a text file of between 68 and 128 bytes ^[1] that is a legitimate executable file called a COM file that can be run by MS-DOS, some work-alikes, and its successors OS/2 and Windows (except for 64-bit due to 16-bit limitations). When executed, the EICAR test file will print "EICAR-STANDARD-ANTIVIRUS-TEST-FILE!" and then will stop. The test string was engineered to consist of ASCII human-readable characters, easily created using a standard computer keyboard. It makes use of self-modifying code to work around technical issues that this constraint imposes on the execution of the test string.

The EICAR test string^[2] reads:

X5O!P%@AP[4\PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*

See also

• GTUBE – a similar test for unsolicited bulk email (e-mail spam)

References

External links

• Official Site of the European Institute For Computer Antivirus Research (also known as the European Expert Group for IT-Security)
• Assembly-language analysis of the EICAR test file
• Let's have fun with EICAR test file – detailed information and assembly analysis
• Test Files and Product Evaluation: the Case for and against Malware Simulation
• Antivirus results from scanning the EICAR file