Authored by Margit Hazenbroek At Fox-IT (part of NCC Group) identifying servers that host nefarious activities is a critical aspect of our threat intelligence. One approach involves looking for anomalies in responses of HTTP servers. Sometimes cybercriminals that host malicious servers employ tactics that involve mimicking the responses of legitimate software to evade detection. However, … Continue reading The Spelling Police: Searching for Malicious HTTP Servers by Identifying Typos in HTTP Responses
Popping Blisters for research: An overview of past payloads and exploring recent developments
Authored by Mick Koomen Summary Blister is a piece of malware that loads a payload embedded inside it. We provide an overview of payloads dropped by the Blister loader based on 137 unpacked samples from the past one and a half years and take a look at recent activity of Blister. The overview shows that … Continue reading Popping Blisters for research: An overview of past payloads and exploring recent developments
From ERMAC to Hook: Investigating the technical differences between two Android malware variants
Authored by Joshua Kamp (main author) and Alberto Segura. Summary Hook and ERMAC are Android based malware families that are both advertised by the actor named “DukeEugene”. Hook is the latest variant to be released by this actor and was first announced at the start of 2023. In this announcement, the actor claims that Hook … Continue reading From ERMAC to Hook: Investigating the technical differences between two Android malware variants
Approximately 2000 Citrix NetScalers backdoored in mass-exploitation campaign
Fox-IT (part of NCC Group) has uncovered a large-scale exploitation campaign of Citrix NetScalers in a joint effort with the Dutch Institute of Vulnerability Disclosure (DIVD). An adversary appears to have exploited CVE-2023-3519 in an automated fashion, placing webshells on vulnerable NetScalers to gain persistent access. The adversary can execute arbitrary commands with this webshell, … Continue reading Approximately 2000 Citrix NetScalers backdoored in mass-exploitation campaign
From Backup to Backdoor: Exploitation of CVE-2022-36537 in R1Soft Server Backup Manager
Blog updated on 3 March 2023 to (i) remove a table containing data created on 09-01-23, more than one month earlier than publication of the original blog on 22-02-23 entitled ‘Backdoored ConnectWise R1Soft Server Backup Manager by Autonomous System Organization (Top 20 as of 2023-01-09)’; (ii) update a table containing data created on 09-01-23 entitled … Continue reading From Backup to Backdoor: Exploitation of CVE-2022-36537 in R1Soft Server Backup Manager
Threat spotlight: Hydra
This publication is part of our Annual Threat Monitor report that was released on the 8th of Febuary 2023. The Annual threat Monitor report can be found here. Authored by Alberto Segura Introduction Hydra, also known as BianLian, has been one of the most active mobile banking malware families in 2022, alongside Sharkbot and Flubot … Continue reading Threat spotlight: Hydra
CVE-2022-27510, CVE-2022-27518 – Measuring Citrix ADC & Gateway version adoption on the Internet
Authored by Yun Zheng Hu Recently, two critical vulnerabilities were reported in Citrix ADC and Citrix Gateway; where one of them was being exploited in the wild by a threat actor. Due to these vulnerabilities being exploitable remotely and given the situation of past Citrix vulnerabilities, RIFT started to research on how to identify the … Continue reading CVE-2022-27510, CVE-2022-27518 – Measuring Citrix ADC & Gateway version adoption on the Internet
One Year Since Log4Shell: Lessons Learned for the next ‘code red’
Authored by Edwin van Vliet and Max Groot One year ago, Fox-IT and NCC Group released their blogpost detailing findings on detecting & responding to exploitation of CVE-2021-44228, better known as ‘Log4Shell’. Log4Shell was a textbook example of a code red scenario: exploitation was trivial, the software was widely used in all sorts of applications … Continue reading One Year Since Log4Shell: Lessons Learned for the next ‘code red’
I’m in your hypervisor, collecting your evidence
Authored by Erik Schamper Data acquisition during incident response engagements is always a big exercise, both for us and our clients. It’s rarely smooth sailing, and we usually encounter a hiccup or two. Fox-IT’s approach to enterprise scale incident response for the past few years has been to collect small forensic artefact packages using our … Continue reading I’m in your hypervisor, collecting your evidence
Sharkbot is back in Google Play
Authored by Alberto Segura (main author) and Mike Stokkel (co-author) Introduction After we discovered in February 2022 the SharkBotDropper in Google Play posing as a fake Android antivirus and cleaner, now we have detected a new version of this dropper active in the Google Play and dropping a new version of Sharkbot.This new dropper doesn't … Continue reading Sharkbot is back in Google Play