VBS/Joint-A
Threat Scorecard
EnigmaSoft Threat Scorecard
EnigmaSoft Threat Scorecards are assessment reports for different malware threats which have been collected and analyzed by our research team. EnigmaSoft Threat Scorecards evaluate and rank threats using several metrics including real-world and potential risk factors, trends, frequency, prevalence, and persistence. EnigmaSoft Threat Scorecards are updated regularly based on our research data and metrics and are useful for a wide range of computer users, from end users seeking solutions to remove malware from their systems to security experts analyzing threats.
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Popularity Rank: The ranking of a particular threat in EnigmaSoft’s Threat Database.
Severity Level: The determined severity level of an object, represented numerically, based on our risk modeling process and research, as explained in our Threat Assessment Criteria.
Infected Computers: The number of confirmed and suspected cases of a particular threat detected on infected computers as reported by SpyHunter.
See also Threat Assessment Criteria.
| Popularity Rank: | 2,135 |
| Threat Level: | 50 % (Medium) |
| Infected Computers: | 76,513 |
| First Seen: | December 7, 2011 |
| Last Seen: | May 4, 2026 |
| OS(es) Affected: | Windows |
VBS/Joint-A is a malware infection written in Visual Basic. The latest variants of VBS/Joint-A were detected in summer of 2011. VBS/Joint-A is a dangerous malware infection that should be dealt with immediately. This kind of infection is usually severe and can have grave consequences on the infected computer system. VBS/Joint-A was first released in October of 2008 and, while Microsoft has released several updates in order to protect users from this infection, variants continue to appear in order to continue attacking computer systems from all around the world.
Table of Contents
Symptoms and Malicious Actions of VBS/Joint-A
The main purpose of VBS/Joint-A is to spread from one computer to another. VBS/Joint-A does this by copying itself to any hard drives that VBS/Joint-A detects, any external memory devices and shared files on the infected computer's network. VBS/Joint-A will usually be associated with another malware infection (usually a backdoor Trojan) which takes advantage of VBS/Joint-A's capacity to spread from one computer to the next in order to deliver its harmful payload. One of the most dangerous aspects of VBS/Joint-A is that a computer system that is infected with this malware threat will often display no signs of a malware infection. Because of this, the first sign of an infection may be a warning from your anti-malware program. This makes maintaining your security software fully updated extremely important.
Elements of a VBS/Joint-A Worm Infection
VBS/Joint-A will usually involve four components with four different extensions: INF, BAT, REG, and VBS. Autorun.inf, which is the autorun configuration data file. This file is responsible for executing VBS/Joint-A automatically. This means that simply plugging in an infected external memory device is enough to infect an entire computer system. The file with the BAT extension is the batch script for this malware threat, and the file with the REG extension is the registry data import file. The worm itself is contained in the VBS extension file. The actual file names vary from one version of VBS/Joint-A to another. VBS/Joint-A makes changes to the Windows Registry so that VBS/Joint-A will run the batch script in the BAT file. This will prevent Windows from loading any security software and blocks certain types of files. VBS/Joint-A will always attempt to copy itself to all drives detected on the infected computer.
Analysis Report
General information
| Family Name: | Worm.Brontok.A |
|---|---|
| Signature status: | No Signature |
Known Samples
Known Samples
This section lists other file samples believed to be associated with this family.|
MD5:
9d3a34c3c292b93df25a539c010c65d0
SHA1:
8eb19eee7c8e32bcc37d81dc712fd7b32b7f3ebe
SHA256:
A97A426DF44FEECBFB26CF136ADD640D73351A9B1AFCE25D4308883AD9D4EE80
File Size:
277.47 KB, 277473 bytes
|
Windows Portable Executable Attributes
- File doesn't have "Rich" header
- File doesn't have debug information
- File doesn't have exports table
- File doesn't have relocations information
- File doesn't have security information
- File is 32-bit executable
- File is either console or GUI application
- File is GUI application (IMAGE_SUBSYSTEM_WINDOWS_GUI)
- File is Native application (NOT .NET application)
- File is not packed
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- IMAGE_FILE_DLL is not set inside PE header (Executable)
- IMAGE_FILE_EXECUTABLE_IMAGE is set inside PE header (Executable Image)
File Icons
File Icons
This section displays icon resources found within family samples. Malware often replicates icons commonly associated with legitimate software to mislead users into believing the malware is safe.
Windows PE Version Information
Windows PE Version Information
This section displays values and attributes that have been set in the Windows file version information data structure for samples within this family. To mislead users, malware actors often add fake version information mimicking legitimate software.| Name | Value |
|---|---|
| Company Name | Microsoft |
| File Version | 1.00 |
| Internal Name | Win |
| Original Filename | Win.exe |
| Product Name | Win |
| Product Version | 1.00 |
File Traits
- HighEntropy
- x86
Windows API Usage
Windows API Usage
This section lists Windows API calls that are used by the samples in this family. Windows API usage analysis is a valuable tool that can help identify malicious activity, such as keylogging, security privilege escalation, data encryption, data exfiltration, interference with antivirus software, and network request manipulation.| Category | API |
|---|---|
| Other Suspicious |
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