Home Malware Programs Backdoors Backdoor.Fexel


Posted: September 25, 2013

Threat Metric

Threat Level: 1/10
Infected PCs: 115
First Seen: September 25, 2013
Last Seen: June 29, 2023
OS(es) Affected: Windows

Fexel, sometimes referred to as Hikit or Deputy Dog, is a backdoor Trojan that provides remote third parties with access to the infected computer. While Fexel may be associated with Axiom, a Chinese threat group, Fexel poses a danger to PCs far outside of that nation's boundaries. Fexel may be installed by other threats (such as Sensode) while disguised as a harmless file. Identifying and deleting Fexel is crucial for any infected PC's safety, but its minimal symptoms and the likely presence of multiple threats cause malware researchers to encourage using automated tools for such purposes.

The Fallout of a Little System Information

Axiom has become known for its multiple-step threat campaigns, eschewing attacks against the general public in favor of targeting well-placed corporate or government entities. Fexel is one of the many types of PC threats that may be employed by this group and provides general backdoor access to the infected PC. Hackers may use Fexel to exploit your PC as a proxy server, launch corrupted files, upload stolen files or download threats. Typically, Fexel conducts these attacks through instructions received through port 443. Unlike the Hikit rootkit (another backdoor threat that serves similar purposes), Fexel may make active contact with a C&C server, which may let security solutions identify Fexel by its outgoing traffic.

As part of its default behavior, Fexel gathers and sends basic system information, such as the version of your OS. Third parties may exploit this information to launch further attacks against infected machines. As with most Axiom threats, malware researchers observed that Fexel's data transmissions used encoding methods meant to block Fexel from being identified very easily. Systems vulnerable to Fexel Trojans include Windows XP, 2000, Vista and 7.

Keeping a Chinese Trojan Out of Your PC's Borders

Axiom is a well-organized group that has demonstrated proficiency with a range of sophisticated threats, as well as the ability to diversify between campaigns to minimize interconnections that would provide PC security institutions with evidence for analysis. While Fexel is not a probable Trojan to find on a home PC, Fexel poses a significant threat to PCs in various industrial sectors and government branches. Particularly targeted regions include much of Europe, the United States and southeast Asia. Telltale signs of this group's sophistication include the use of stolen digital certificates to provide fraudulent identity pretenses, which may provide another layer of disguised for Fexel and other Axiom threats.

There are no symptoms associated with Fexel's attacks, other than, of course, the hopefully-present warnings of relevant anti-malware features. In some cases, Fexel also may include rootkit technology, and Fexel may install a secondary driver in a separate directory. Generous systems scans by good anti-malware products are, as usual, recommended for uninstalling Fexel or other backdoor Trojans.

Technical Details

File System Modifications

Tutorials: If you wish to learn how to remove malware components manually, you can read the tutorials on how to find malware, kill unwanted processes, remove malicious DLLs and delete other harmful files. Always be sure to back up your PC before making any changes.

The following files were created in the system:

%UserProfile%\Aplication Data\[8 HEXADECIMAL DIGITS].dll File name: %UserProfile%\Aplication Data\[8 HEXADECIMAL DIGITS].dll
File type: Dynamic link library
Mime Type: unknown/dll
Group: Malware file

Registry Modifications

The following newly produced Registry Values are:

HKEY..\..\{Value}HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\"[8 HEXADECIMAL DIGITS]" = "rundll32.exe "%SystemDrive%\Documents and Settings\All Users\Application Data\[8 HEXADECIMAL DIGITS].dll",Launch"HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run\"[8 HEXADECIMAL DIGITS]" = "rundll32.exe \%SystemDrive%\Documents and Settings\All Users\[8_hex_digits].dll\"