List of “朝長 秀誠 (Shusei Tomonaga)”

  • Attack Convincing Users to Download a Malware-Containing Shortcut File Malware
    Attack Convincing Users to Download a Malware-Containing Shortcut File
    Beginning in April 2019, JPCERT/CC has been observing attacks where targeted emails are distributed to Japanese organisations, aiming to convince recipients to download a malicious shortcut file. These emails contain a link to a shortcut file on a cloud service. When this shortcut file is executed, a downloader launches. This article is to describe the details of the downloader and the behaviour that follows. How the downloader is launched The...

    Read more

  • Bug in Malware “TSCookie” - Fails to Read Configuration - (Update) Malware
    Bug in Malware “TSCookie” - Fails to Read Configuration - (Update)
    Our past article has presented a bug in malware “TSCookie”, which is reportedly used by BlackTech attack group. This article is to update the features of the malware. Even after we published the blog article in October 2018, the adversary had continued using the malware as it was. Just in May 2019, we confirmed that the malware had its bug fixed and was used in some attack cases. Details of...

    Read more

  • Bug in Malware “TSCookie” - Fails to Read Configuration - Malware
    Bug in Malware “TSCookie” - Fails to Read Configuration -
    In a previous article we have introduced malware ‘TSCookie’, which is assumedly used by an attacker group BlackTech. We have been observing continuous attack activities using the malware until now. In the investigation of an attack observed around August 2018, we have confirmed that there was an update in the malware. There are two points meriting attention in this update: Communication with CC server Decoding configuration information This article will...

    Read more

  • Malware “WellMess” Targeting Linux and Windows Malware
    Malware “WellMess” Targeting Linux and Windows
    Some malware is designed to run on multiple platforms, and most commonly they are written in Java. For example, Adwind malware (introduced in a past article) is written in Java, and it runs on Windows and other OS. Golang is another programming language, and it is used for Mirai controller, which infects Linux systems. This article introduces the behaviour of WellMess malware based on our observation. It is a type...

    Read more

  • PLEAD Downloader Used by BlackTech Malware
    PLEAD Downloader Used by BlackTech
    In a past article, we introduced TSCookie, malware which seems to be used by BlackTech[1]. It has been revealed that this actor also uses another type of malware “PLEAD”. (“PLEAD” is referred to both as a name of malware including TSCookie and its attack campaign [2]. In this article, we refer to “PLEAD” as a type malware apart from TSCookie.) PLEAD has two kinds – RAT (Remote Access Tool) and...

    Read more

  • Malware “TSCookie” Malware
    Malware “TSCookie”
    Around 17 January 2018, there were some reports on the social media about malicious emails purporting to be from Ministry of Education, Culture, Sports, Science and Technology of Japan [1]. This email contains a URL leading to a malware called “TSCookie”. (Trend Micro calls it “PLEAD” malware [2]. Since PLEAD is also referred to as an attack campaign, we call this malware TSCookie in this article.) TSCookie has been observed...

    Read more

  • Investigate Unauthorised Logon Attempts using LogonTracer Forensic
    Investigate Unauthorised Logon Attempts using LogonTracer
    In the recent article, we introduced the concept and the use of "LogonTracer", a tool to support Windows event log analysis. This article presents how unauthorised logon attempts can be identified using this tool. Please refer to the Wiki for LogonTracer installation. Points for Investigation LogonTracer serves as a tool to support the log analysis rather than to detect unauthorised logon itself. For an effective investigation using this tool, we...

    Read more

  • Research Report Released: Detecting Lateral Movement through Tracking Event Logs (Version 2) Forensic
    Research Report Released: Detecting Lateral Movement through Tracking Event Logs (Version 2)
    In June 2017, JPCERT/CC released a report “Detecting Lateral Movement through Tracking Event Logs” on tools and commands that are likely used by attackers in lateral movement, and traces that are left on Windows OS as a result of such tool/command execution. After the release, we received a lot of feedback on the report, and until now we had been working on the revision based on the comments. Today, we...

    Read more

  • Visualise Event Logs to Identify Compromised Accounts - LogonTracer - Forensic
    Visualise Event Logs to Identify Compromised Accounts - LogonTracer -
    Hello again, this is Shusei Tomonaga from the Analysis Center. Event log analysis is a key element in security incident investigation. If a network is managed by Active Directory (hereafter, AD), can be identified by analysing AD event logs. For such investigation, it is quite difficult to conduct detailed analysis in AD event viewer; it is rather common to export the logs to text format or import them into SIEM/log...

    Read more

  • Clustering Malware Variants Using “impfuzzy for Neo4j” Malware
    Clustering Malware Variants Using “impfuzzy for Neo4j”
    In a past article, we introduced “impfuzzy for Neo4j”, a tool to visualise results of malware clustering (developed by JPCERT/CC). In this article, we will show the result of clustering Emdivi using the tool. Emdivi had been seen until around 2015 in targeted attacks against Japanese organisations. For more information about Emdivi, please refer to JPCERT/CC’s report. Clustering Emdivi with impfuzzy for Neo4j Emdivi has two major variants - t17...

    Read more