image spam


Also found in: Dictionary, Thesaurus, Medical, Wikipedia.

image spam

An email advertisement in the form of an image in the message rather than text in order to avoid detection as spam. Spam filters typically analyze words in a message, which is relatively fast, but scanning images with optical character recognition (OCR) to extract the text is slow. In addition, spammers have already circumvented optical scanning by fracturing the text within the image similar to the CAPTCHAs on Web page forms (see CAPTCHA). Animated GIFs are also used to spread the text across multiple frames, making it harder to analyze.

Message Fingerprinting
Another defense is to track known image spam and save the attributes of their text and images as signatures that can be quickly analyzed. In many cases, the fingerprint need only be of the image. Although this is a faster detection approach, keeping up with the latest image spam signatures is like keeping virus signatures up-to-date. See spam and OCR.


Not Exactly Clear
Many spam images are legible to a human, but this one from Korea-based CLC Holding Company is barely readable. Images such as this are sent because spammers are counting on the one person in 10,000 who will actually take the time to decipher it.
Mentioned in ?
References in periodicals archive ?
Text-based spam still appeals to automated scripts for word scrambling, rephrasing or (synonymic) substitution, while image spam usually deploys obfuscated content.
TRACE said the growing amount of image spam coincides with a fall in the amount of spam containing embedded clickable URL links, which has fallen to around 55% of spam, compared to 96% in 2004.
Engate is impenetrable to threats because its proprietary technology uses protocol information that can never be forged, resulting in a permanent solution for all threats such as image spam, phish and botnets.
According to the company, the third generation of image spam defence incorporates a new multi-pass optical character recognition (OCR) engine.
Because developing stock spam that can pass through popular spam filters often requires the spammer to degrade the readability of the messages, stock spam also makes up a significant percentage of image spam.
These include RPD along with Zombie detection, IP reputation, image spam defence, heuristic and Bayesian engines.
Tumbleweed's MailGate appliance filters a new image, using the wavelet transform technique to compare the image to existing image spam signatures, ensuring spam with similar but slightly varying graphics is blocked.
In addition, Cloudmark stops messaging threats in any protocol, format (including image spam, .
This reduces a lot of the horsepower problems associated with processing image spam.
In addition, Cloudmark stops messaging threats in any language, protocol or format (including image spam, .
SoftScan attributes the enlargement of file size to the noticeable rise in image spam in recent months and warns that this will add to the cost managing email for some organisations that have to scale-up bandwidth and storage requirements to meet demands.
TELECOMWORLDWIRE-24 January 2007-Marshal's TRACE team claims image spam has reached new levels(C)1994-2007 M2 COMMUNICATIONS LTD http://www.