Security in Windows Server 2019

At the end of last December, Microsoft published a document titled What’s new in Windows Server 2019, covering the new features and renewed functionalities provided by the new version of Windows Server. This post will focus on those features related to security improvements provided by Windows Defender ATP that had already been seen in Windows 10 through Windows Defender Exploit Guard, EMET (Enhanced Mitigation Experience Toolkit, which ceased to have support last July 31, 2018), as well as WDAC (Windows Defender Application Control).... Leer Más

EternalSilence: Why your router may be at risk from this NSA tool

Today’s article is courtesy of John Mason, co-founder of  TheBestVPN.com and writer at TripwireStaySafeOnline, DigitalGuardian y Educause. You can find him on twitter as @JohnCyberMason.

Do you trust your router to keep you safe from hackers and spies? You may want to take another look just to make sure.

Akamai recently discovered a malware campaign that has already compromised over 45,113 home and office routers. This was done using a tool based on the United States of America’s NSA hacking tools which were leaked online in 2017. To explain how hackers use this tool to turn your router into a proxy server, we first have to understand how UPnP works.

UPnP is a protocol that eases device and service discovery as well as the configuration of consumer devices and networks. Its primary purpose was to allow devices on a LAN to automatically expose services and functionality other devices on the local network.

[Read more…]

Analysis of Linux.Haikai: inside the source code

A few days ago we got the source code of the Haikai malware, which corresponds to one of the many implementations carried out by the continuous recycling of source code belonging to different IoT botnets. Although we have not identified any new developments compared to previous IoT malware versions, it has allowed us to obtain a lot of information on techniques, improvements and authors.

It should also be noted that, according to different records obtained, this botnet has been in operation for most of the last month of June.

In the following lines the code will be analyzed, as well as the possible attributions and the implementations not referenced in the execution thread, which allow us to guess that the code is mutating in different lines in parallel for the same function.

So let’s start by analyzing the structure of the files. [Read more…]

Exchange forensics: The mysterious case of ghost mail (I)

Articles in the series “Exchange forensics: The mysterious case of ghost mail”: [1] [2] [3] [4]

(Note: This is a fiction story, the characters and situations are not real, the only real thing is the technical part, which is based on a mixture of work done, experiences of other colleagues and research carried out. If you want a version with the same technical dose but with less narrative, you can consult the video of the talk that the author gave at the 11th STIC Conference of the CCN-CERT here).

Another day in the office, with a list of pending tasks to plan longer than the beard of Richard Stallman and none of them entertaining: reports, documentation of a couple of projects and the preparation of a meeting is what the menu of the day offers for almost the entire week.
Luckily, the saying that “no plan survives contact with the enemy” in this case works in our favor. The phone rings, and my boss goes straight to the point: “A YARA rule has been triggered from the ATD group in CARMEN of [Redacted] (entity whose identity we are going to leave anonymously, calling it “the Organization” from now on). Take your stuff and rush over there.”

The adrenaline rush at the thrill of the hunt is instantaneous: ATD is our internal name of a group of attackers that we hunted a few months ago on another client, and our reversers ripped the malware open from top to bottom without mercy. The analysis allowed us to detect a series of particular “irregularities” in their way of acting, which allowed us to generate a series of high fidelity YARA rules (that is, false positives practically null). If it was triggered on CARMEN (our advanced intrusion detection tool), then 99% sure to be infected”.
[Read more…]

‘Reversing’ of malware network protocols with ‘angr’

One of the most difficult objectives to obtain in the analysis of a malicious binary is usually discovering all of the functionalities that it has. If in addition, these functions are only executed at the discretion of the attackers through its control center, things get complicated. For various reasons, many times we cannot carry out a full dynamic analysis, such as the fall of the malware infrastructure or the isolation of the sample to avoid contact with the C&C. In these cases the analysis of the interaction between the server of the attacker and the sample is usually slower, since you have to create a fictitious server or be continually patching/deceiving the sample, to take it through all the different paths that we want to investigate. Depending on the size and complexity of the analyzed code or the objective of the analysis, this task can vary its difficulty and extension over time.

I am going to propose a study example of the functionalities of a fictitious RAT that can be executed according to the orders received from your C&C panel. Our goal would be to create a server that simulates the attacker’s. For this we have to understand the communication protocol between the server and the sample installed on the victim’s device.

[Read more…]

Some vulnerability in ASUS routers

A few months ago, I changed my old TP-LINK router to an ASUS. Since it is the de facto manufacturer recommended by my ISP, in order to avoid any complications that could lead to delays in getting my Internet up and running I decided to go with it.

Then comes a lonely afternoon of boredom, or perhaps out of habit (I wanted to start writing a report:D), so I start by trying a little apostrophe here, a marquee as the Wi-Fi name, , command execution in one of the network diagnostic pages and a long list of etc. In the end, one thing leads to another (you know how that goes…), you get involved and when you’re conscious you have Burp or ZAP open, you’ve gone over halfway through OWASP and you’ve been looking for hours for something to play with, something interesting to see how safe your brand-new router is. [Read more…]

Templates with bad intentions

A few days ago while analyzing several emails I came across one that contained a suspicious attachment. It was a .docx document that at first glance had nothing inside but it occupied 10 kb.

The mail had passed all the barriers, both SPF, as the two antiviruses that gateways have, and also the anti-spam filter.

The .docx file can be treated as a tablet. Once extracted its content, I began to analyze all the files in the directory in search of domains or IP addresses that could be seen clearly:

And I managed to find something interesting inside the path word/_rels/document.xml.rels where the following appears:
[Read more…]

Phishing: improving our campaigns

One of the most important things when carrying out a phishing campaign [Obviously, always from legal terms Ed.] is to ensure that our mail gets to evade the anti-spam filters and thus be able to reach the victim’s inbox.

In this post we are not going to explain how Gophish, que ya hemos mencionado en algún post, we will simply explain a series of steps to follow to make our emails more reliable. It is worth adding that following these steps does not ensure 100% success, each mail manager has its own filtering rules.

We start from the basis that Gophish is already installed, so the next step would be to obtain a domain and make a series of changes in DNS administration.
[Read more…]

Analysis of Linux.Helios

For several weeks we have been detecting a new variant of malware for Linux and IoT architectures from the malware laboratory of S2 Grupo, registered for the first time on the VirusTotal platform on October 18, which we have called Linux.Helios, due to the name of certain functions present in the sample.

We emphasize that the main antivirus signatures do not unanimously classify this sample: they range from ELF.DDoS to Tsunami, through Gafgyt or Mirai.
[Read more…]

The mimi (mimikatz) side of #NotPetya

(Please note some of the internal links are in Spanish)
One of the things that most caught our attention from the #NotPetya malware lab is the module that appears to contain code from the mimikatz tool. It is an automation of the process of any pentest that we believe is worth studying and treat it with love, to learn.
For the analysis we focus on the 32-bit version of the binary:
[Read more…]