coastnomad.blogg.se - Avast web shield blocking internet 2018

#AVAST WEB SHIELD BLOCKING INTERNET 2018 ARCHIVE#
#AVAST WEB SHIELD BLOCKING INTERNET 2018 CODE#
#AVAST WEB SHIELD BLOCKING INTERNET 2018 PASSWORD#
#AVAST WEB SHIELD BLOCKING INTERNET 2018 FREE#

What we found in the downloaded RAR archive were two implementations of one algorithm where one implementation extends the other. To provide a better idea of how much they differ, the router models that are targeted in version B are listed in the box. In version B of the source code, all exploit kits are implemented in the Router.py file.

#AVAST WEB SHIELD BLOCKING INTERNET 2018 CODE#

In the picture below, version A of the source code can be seen on the left side and version B on the right side. Number of credentials used in the brute-force attackĪpart from the different targets, these two versions also have a slightly different folder structure. Number of devices with open ports worldwide in May 2020 (shodan.io) Number of devices with open ports in Brazil in May 2020 (shodan.io)

Version B: This implementation targets a significantly higher number of devices and open ports, but the list of default credentials is shorter.

Version A: This implementation of the source code targets a lower number of devices and ports that may be open, but uses a longer list of default credentials to brute-force the correct combination of a username and password.

Based on the analysis of the files, we can separate all the implementations into two groups, or versions, with different targets. The behavior of the malicious script in each version is very similar, but they differ in the implementation details. Based on the files’ metadata the oldest implementation was created in July, 2017. We found five implementations of the GhostDNS source code used in this campaign. BRUT searches for and attacks routers with a public IP address and an HTTP port opened to the internet.

#AVAST WEB SHIELD BLOCKING INTERNET 2018 FREE#

In this part, we will focus on analyzing the source code of a free internet scanner called BRUT. Based on anonymized data from our Avast Wi-fi Inspector feature included in all versions of Avast Antivirus, 76% of router login credentials in Brazil have weak login passwords, leaving them vulnerable. The reason why campaigns like this are successful is because most routers are left vulnerable thanks to weak (usually default) credentials routers and other devices with DNS servers are shipped with. Although the majority of attacks target routers in Brazil, due to the large amount of vulnerable routers. This and similar campaigns usually appear in waves and target routers around the world. Scanners can be used for free, attackers don’t have to pay for clicks, and can control which IP addresses and ports will be scanned and eventually attacked. On the other hand, using an internet scanner, such as BRUT or masscan, to search for vulnerable routers and attacking them from the outside has its benefits for attackers.

The chances of a successful attack on the router using this approach are higher, as many routers are accessible only from the local network. Once the malicious link is clicked on, the attack is launched from the computer, from within the local network. When a malvertising campaign is used to facilitate the attack, an attacker pays for a campaign that is guaranteed to drive a given number of people to their malicious page. The difference between these two attack approaches is significant. There are videos available online explaining how attacks, like this one, can be executed. The name of the file indicates its purpose – it uses a DNS hijack method to redirect users to phishing webpages where a keylogger (KL) is used to obtain users’ credentials or credit card information. The file we downloaded was named ‘KL DNS.rar’, its structure can be seen below. We downloaded the linked file and found the complete source code of the GhostDNS exploit kit.

#AVAST WEB SHIELD BLOCKING INTERNET 2018 PASSWORD#

The user forgot to disable the Avast Web Shield while doing this, and since the archive was not password protected, it was automatically analyzed by the Shield and it triggered our router exploit kit (EK) detections. It turned out that one of our Avast users was up to no good, uploading a RAR archive with malicious content to the server. Router exploit kits are usually distributed via malvertising webpages, and these campaigns appear in waves.Ī year ago (May 2019), our Avast Web Shield, a feature in our antivirus program protecting people from malicious web content, blocked a URL from the file-sharing platform. Router exploit kits are becoming more and more popular among cybercriminals, mostly targeting routers in Brazil, because many Brazilian routers are poorly secured with default and well known login credentials.