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Web Proxy Event Analysis Cheat Sheet

The "Web Proxy Event Analysis Cheat Sheet" can help SOCs and security analysts classify proxy events (blocks, alerts) and is based on my ideas and many ideas from experts that helped me collect detection ideas for this document. You can download version 1.0 here. We...

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How to Fall Victim to Advanced Persistent Threats

During the last four years, I was engaged on incident response teams for several large advanced persistent threat (APT) cases involving different German corporations. In this time, we have developed methods and tools to detect compromised systems, while also planning...

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YARA Rules to Detect Uncommon System File Sizes

YARA is an awesome tool especially for incident responders and forensic investigators. In my scanners I use YARA for anomaly detection on files. I already created some articles on "Detecting System File Anomalies with YARA" which focus on the expected contents of...

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How to Write Simple but Sound Yara Rules – Part 2

How to Write Simple but Sound Yara Rules – Part 2

Months ago I wrote a blog article on "How to write simple but sound Yara rules". Since then the mentioned techniques and tools have improved. I'd like to give you a brief update on certain Yara features that I frequently use and tools that I use to generate and test...

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Splunk Threat Intel IOC Integration via Lookups

Splunk Threat Intel IOC Integration via Lookups

Today most security teams have access to a lot of different information sources. On the one hand they collect log data from different sources and try to correlate them in a useful way in so-called SIEM systems. On the other hand they receive threat information from...

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APT Detection is About Metadata

People often ask me, why we changed the name of our scanner from "IOC" to "APT" scanner and if we did that only for marketing reasons. But don't worry, this blog post is just as little a sales pitch as it is an attempt to create a new product class. I'll show you why...

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How to Write Simple but Sound Yara Rules

How to Write Simple but Sound Yara Rules

During the last 2 years I wrote approximately 2000 Yara rules based on samples found during our incident response investigations. A lot of security professionals noticed that Yara provides an easy and effective way to write custom rules based on strings or byte...

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Bash Schwachstelle CVE-2014-6271 Shell Shock erkennen

Dieser Artikel enthält Information dazu, wie Sie die bash Schwachstelle CVE-2014-6271 Shell Shock erkennen und behandeln können. Betroffene Systeme Grundsätzlich sind alle Systeme betroffen, die eine “bash” einsetzen, also Linux Unix AIX Solaris HPUX D.h. auch viele...

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Inverse Yara Signature Matching (Part 1/2)

Inverse Yara Signature Matching (Part 1/2)

During our investigations we encountered situations in which attackers replaced valid system files with other system files to achieve persistence and establish a backdoor on the systems. The most frequently used method was the replacement of the "sethc.exe" with the...

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Howto detect Ebury SSH Backdoor

Die folgende Yara Signatur kann für die Erkennung der Ebury SSH Backdoor verwendet werden. rule Ebury_SSHD_Malware_Linux { meta: description = "Ebury Malware" author = "Florian Roth" hash = "4a332ea231df95ba813a5914660979a2" strings: $s0 = "keyctl_set_reqkey_keyring"...

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