However, besides the webinjects, there are other sections in the configuration files. With Swatbanker, one of these is a URL filter list. If an infected computer visits a website on this list, it sends data to the control server. This section was empty in previous versions of the malware. In the current analysis, we have found several configuration files between 08/06/2015 11:41 and 10/06/2015 14:21 that have been filtering on domains such as: *bundestag.btg*
This is the domain for the German Bundestag's intranet. When an infected computer calls up a domain that uses this pattern, it reports in to the control server and transfers the following information:
- URL (address of the website visited)
- User agent (details such as the browser used)
- Referrer (details on the source of the request - Called up by clicking on a link? If so, on which site was it clicked on?)
- Content type of the server response (file type that the server sends in its response)
- Content of the POST request in form fields (incl. login name, password, search input)
- The full response from the server (web pages or files that the server returns for the request)
Apparently, the operators of the Swatbanker botnet are interested in whether they have infected computers that can access the intranet pages of the Bundestag. The two days mentioned are sufficient for searching the entire botnet for the relevant zombie computers and at the same time obtaining the access data for the Bundestag's intranet. The server responses also captured can be used to capture the content displayed or prepare for further attacks. The botnet operators would then also be capable of carrying out additional activities such as installing additional malware for spying on the network and collecting additional data or more.
How should this new incident be categorised? Why is another attack on the Bundestag's intranet following where its network is already fully compromised, according to media reports? One possibility might be that this is a separate attack that uses Swatbanker to access a framework specialising in data theft (in the banking environment). Whether the operators of the Swatbanker botnet have taken the initiative themselves or whether they are working on behalf of secret services cannot be said for certain. Related reports that banking Trojans from eastern Europe are being used for targeted attacks are becoming more frequent in certain circles.
However, it might also be that this is a continuation of the original attack. In this scenario, computers that are used in the Bundestag network have mostly been compromised. However, private or mobile computers, on which members of parliament often edit their data, have only partially been involved. The current attack is ideally suited to detecting such external computers and drawing them in to the original attacks.