Black Hole exploits spreading: Symantec

CIOL Bureau
Updated On
New Update

BANGALORE, INDIA: Symantec has cautioned about the BlackHole toolkit, which has a powerful set of exploits and is spreading like wildfire. In a release issued on Monday, Symantec said that at present, it is the most prevalent exploit toolkit in the wild and can easily be compared with the likes of Neosploit and Phoenix in terms of the number of affected users.


Also read: 'Beware of tool kits from malicious sites'

Symantec recently reported the increasing utilization of sophisticated toolkits by criminals who would otherwise lack the technical expertise for cyber attacks, fueling a self-sustaining, profitable, and increasingly organized global economy.

Toolkits account for 61 per cent of all threat activity on malicious websites


In recent times, BlackHole has clearly emerged as the most used toolkit among hackers. The following IPS graph proves this fact, since more than 100,000 malicious hits are reported each day:

How BlackHole works:


·         When victims visits a clean site that has been injected with a malicious iFrame, they are redirected to the BlackHole exploit kit server. BlackHole obfuscates the exploits for popular vulnerabilities such as PDF, JAVA, HCP, MDAC, etc.

·         The page contains the code that redirects the user to download a malicious jar file. One of the classes inside the jar file extracts the value passed to it in the script, and then decodes it into a URL. This URL is then used to perform other malicious downloads.

·         The URL downloads Trojan.Carberp, which is a highly sophisticated Trojan that is being compared to ZeuS because of its ingenious techniques for avoiding detection.


·         The Trojan posts a unique ID to the command-and-control (C&C) server that will be used every time a transaction takes place between the Trojan and the C&C server. Next, the Trojan will post all of the running processes on the victim’s computer to the C&C server.

Also read: One in 10 computers vulnerable to cyber attack

·         The Trojan then downloads three modules:


o    stopav.plug — This module disables the antivirus installed on the victim’s computer.

o    miniav.plug — Checks for the presence of other Trojans, such as Zeus, and if found, the Trojan deletes its  competitor(s).

o    passw.plug — It will log every username/password combination that is typed, as well as any URLs visited.


·         The C&C server sends the “multidownload” command to the Trojan:

o    The first file downloaded is Trojan Hiloti (a.k.a. Trojan.Zefarch), which makes requests to a free file-hosting site.

o    The second file downloaded (2.exe) is FakeAV