The Delf Trojan is a dangerous weapon used against computer users worldwide. It infects mainly via infected software installers. Our article gives an overview of its behavior according to the collected samples and available reports, also it may be helpful in attempting to remove the virus.
|Short Description||The Delf Trojan is a computer virus that is designed to silently infiltrate computer systems.|
|Symptoms||The victims may not experience any apparent symptoms of infection.|
|Distribution Method||Software Vulnerabilities, Freeware Installations, Bundled Packages, Scripts and others.|
|Detection Tool|| See If Your System Has Been Affected by Delf Trojan |
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|User Experience||Join Our Forum to Discuss Delf Trojan.|
Delf Trojan – Distribution Methods
The Delf Trojan is a generic identifier of several related threats. All of them use similar behavior patterns and distribution techniques allowing it to gain access to the target systems. The attack campaigns that are used to carry this Trojan can use the most popular methods to infect victims:
- Email Phishing Tactics — The criminals can conduct campaigns that seek to coerce the recipients into thinking that they have received a legitimate email from a well-known service or company. They are modeled after the real notifications and might include stolen content. Whenever one of the elements is accessed by the victims the Trojan will be delivered. The samples can also be directly attached to the messages as well.
- Malicious Download Pages — The criminals can create fake download sites, landing pages and portals to spread the Trojan. Other elements that can lead to the malware infection are all forms of interactive content: pop-ups, banners, ads and etc.
- Malicious Documents — The criminals can embed the virus installation scripts in documents of all popular types: spreadsheets, presentations, text files and databases. They depend on the execution of the built-in macros which are programmed to execute the Delf Trojan as soon as permission is granted to run them. This is done by spawning a pop-up notification asking the users to enable them in order to “correctly view” the file.
- Virus Setup Files — The other possibility is to embed the necessary malicious code in application setup files. The hackers will take the real installers and modify them with the code which is released via the methods described in this articles. Take note that all of the popular software can be affected: system utilities, creativity suites, productivity and office apps and etc.
- File Sharing Networks — The use of networks like BitTorrent for spreading Trojan samples is one of the most effective infection mechanisms. They are widely used to spread both legitimate and pirate content.
- Browser Plugins — They are made compatible with most of the popular web browsers and can often be found on the relevant browser repositories. They are uploaded with fake user reviews and developer credentials and promise feature additions and performance optimizations. However once they are installed dangerous modifications will take place to the computers — both the virus will be delivered and the victims may be redirected to a hacker-controlled landing page every time they start the browser.
Depending on the exact hacker configuration various other methods can also be used to spread the Delf Trojan.
Delf Trojan – Detailed Description
All of the classified so far Delf Trojan variants follow a typical behavior pattern which is slightly changed between the different variants. The slight code changes are the primary signs for differentiating between them.
As soon as the Del Trojan infection is triggered it will deploy various files to the Windows system folder. A distinct characteristic is that one of the files is a legitimate copy of the Windows file to fool the system security scans into thinking that a legitimate operation is being done. By modifying the folder and configuration files the Delf Trojan will automatically be started once the computer is powered on. A distinct Windows Registry key will be created specifically for the Trojan service.
Some of the Delf Trojan samples are capable of hooking up to other processes and services, including Internet Explorer. This allow the virus to carry out code injection attacks — modifications of input/output data and reading of the user interaction in real-time. This gives the Delf Trojan the ability to spy on the activities in real-time and modify form data. Such actions are widely used when the victims access online banking systems. Transaction details are changed in real-time leading to funds transfer to hacker banking accounts without the users noticing.
The Trojan code can retrieve data from the compromised machines which can be categorized into two groups:
- Personal User Information — The engine can be configured to gather sensitive information about the victims which can be used for blackmail, identity theft and financial abuse crimes. This is done by instructing the Trojan to look for information such as their name, address, phone number, location and any stored username and password combinations.
- Machine Identification — A detailed report of the installed components is made. It includes information on the parts, user settings and operating system values. This is used to compute an unique machine ID that is assigned to each host.
By taking advantage of the extracted information the Delf Trojan can scan for any security software that can block or remove it. Their real-time engines can be bypassed if the latest signatures are not available. So far the samples indicate that this mechanism acts against the following programs:
360safe, duba, kaspersky, mcafee, nod32, rising, Symantec AntiVirus
The Delf Trojan is fully capable of modifying boot options and configuration files in order to automatically start itself when the computer is powered on. This may also render most manual removal guides non-working as access to the boot recovery menu can be disabled.
The main goal of this malware is to run the built-in Trojan module which establishes a secure connection to a hacker-controlled server. It allows the operators to take over control of the machines, steal files and spy the victims in real time. Several distinct commands have been identified in some of the samples: HEAD, POST, OPTIONS, TRACE, PUT and CONNECT. The security reports indicate that there are several scenarios that can be launched:
- Data Theft — The connections can be used to program files theft from the compromised networks and any accessible removable storage devices or network shares.
- DDoS Weapon — When a large number of compromised networks have been acquired they can be programmed to direct a concurrent attack on a given target. This can take down both companies and government agencies.
- Proxy Server — Other malicious infections are done by the hackers via network proxies. The infected machines serve as the proxies from which the crimes are done.
Some of the acquired Delf Trojan files can scan the contents of files which are analyzed for email addressees. They will be forwarded to a database from which phishing messages are sent. Captured samples of this type have been found to target the following data:
.adb, .dbx, .doc, .eml, .htm, .html, .mbx, .mdx, .msg, .nch, .not, .oft,
.rtf, .sht, .tbb, .tbi, .txt, .wab, .xls,. xml
The addresses will be discarded if the following keywords are identified:
.edu, .gov, .mil, abuse, adres, admin, anonymous, anti, anyone, aol, apache,
avp, berkeley, borlan, bsd, bug, certific, contact, cops, defend, echo, example,
fbi, fido, foo, google, gov, help, ibm.com, icrosof, info, npris, kaspersk,
kernel, linux, local, mcafee, microsof, mozilla, mydomai, nobody, nodomai,
norton, not, nothing, page, panda, pgp, policy, postmaster, privacy, random,
reply, report, ripe, root, samples, secur, sendmail, service, spam, submit, support,
symantec, user, virus, webmaster, webmin, webmist
Some of the example subject lines that carry the Delf Trojan code are the following:
- Crazy soccer fans
- My sister whores, sh[*]t i dont know
- My tricks for you
- Naked World Cup game set
- Please reply me Tomas
- Soccer fans killed five teens
Remove NtCrypt Crypter Completely
To remove Delf Trojan manually from your computer, follow the step-by-step removal tutorial written down below. In case this manual removal does not get rid of the miner malware completely, you should search for and remove any leftover items with an advanced anti-malware tool. Such software can keep your computer secure in the future.