Trojan.Zbot.J
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.
EnigmaSoft Threat Scorecards display a variety of useful information, including:
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: | 14,269 |
| Threat Level: | 80 % (High) |
| Infected Computers: | 57 |
| First Seen: | February 7, 2019 |
| Last Seen: | June 25, 2026 |
| OS(es) Affected: | Windows |
Trojan.Zbot.J is a heuristic detection name used to flag a 32-bit Windows executable belonging to the long-lived Zeus (also written Zbot) family of information-stealing banking Trojans. The ".J" suffix denotes a specific variant cluster inside the broader Zbot signature set. Files carrying this label are designed to run quietly in the background, harvest credentials and financial data, and hand remote operators control over the compromised host.
The sample analyzed for this report is a small, unsigned x86 PE binary. While the Zeus lineage dates back to the late 2000s, its leaked source code has kept it and its descendants in circulation for more than a decade, which is why detections such as Trojan.Zbot.J still appear on modern systems.
Table of Contents
What Is Trojan.Zbot.J?
Trojan.Zbot.J is a member of the Zeus/Zbot banking-Trojan family. Zeus first surfaced publicly around 2007 and quickly became one of the most notorious credential-stealing kits ever built. It is engineered to steal confidential information from an infected machine — system details, saved credentials, browser session data and, above all, online-banking usernames, passwords and one-time two-factor codes.
Zeus earned its reputation through two signature techniques: form grabbing (intercepting data typed into web forms before it is encrypted and sent) and man-in-the-browser injection, in which the malware alters what a victim sees inside their banking session in real time. When the full Zeus 2.0.8.9 source code was leaked in mid-2011, it spawned an entire ecosystem of successors — including Citadel, Ice IX, KINS and Gameover Zeus — which is a major reason the Zbot detection family remains so broad. A detection of Trojan.Zbot.J should therefore be treated as a serious credential-theft incident, not a low-risk nuisance.
How It Spreads / Distribution
Historically, Zeus/Zbot binaries have reached victims through a handful of well-documented delivery channels. The most common is malicious email — phishing messages carrying weaponized attachments or links to attacker-controlled download pages. Exploit kits embedded in compromised or malicious websites have also been used to drop Zbot silently during "drive-by" visits. In many campaigns the Trojan is paired with additional payloads; Zeus operators have historically used it as a loader to deliver secondary malware, including ransomware such as CryptoLocker.
Because the leaked builder is freely available, individual campaigns vary widely: a given Trojan.Zbot.J file may be seeded by a botnet spam run, bundled inside cracked-software installers, or dropped by another infection already resident on the machine. The small on-disk footprint of the analyzed sample (roughly 44 KB) is consistent with a lightweight stealer/loader that is easy to attach to an email or stage from a compromised site.
Technical Analysis & Behavior
The representative sample examined here is a 32-bit (x86) Windows Portable Executable of 45,056 bytes. Static inspection shows a binary that is not validly digitally signed (no verified signer or root is present), and the automated analysis flagged a nonzero set of PE header characteristics — the kind of structural anomalies that generic packer/loader heuristics key on. No packer was positively identified for this specific object, and the sandbox run recorded no dynamic behavior categories, registry modifications or file-write operations for this sample. That pattern is common with Zbot objects that are staged, dormant, environment-aware, or that require a live command-and-control channel before they detonate; it does not lower the family's underlying risk.
Drawing on well-established public documentation of the Zeus/Zbot family (Microsoft, Sophos, Proofpoint, MITRE ATT&CK and independent analyses), a fully executing member of this family typically performs the following actions on a real host: it injects code into legitimate processes to hide and to gain access to browser memory; it installs form-grabbing and keylogging hooks to capture credentials as they are entered; it enumerates the system (for example via systeminfo-style discovery, ATT&CK T1082); it establishes persistence through registry autostart keys; and it beacons to remote command-and-control infrastructure to receive configuration files, exfiltrate stolen data and pull additional payloads. These are documented family traits and are attributed to public sources — they were not all observed in this particular sandbox run.
Indicators of Compromise
The following indicators come directly from the analyzed sample. These values reflect one analyzed sample; specific indicators rotate frequently between builds, so absence of an exact match does not rule out an infection.
- MD5: 4542cc147e9eee9e271dea72e1a58a93
- SHA-1: f933688962af3999b11692a394837af8e5aa3ff5
- SHA-256: 6273E21CBAA594A4883876B0C58A9DEE0024185FA3C5349FF5C93249887A30B9
- File size: 45,056 bytes (~44 KB)
- Architecture: x86 (32-bit PE)
- Digital signature: not validly signed — no verified signer or root certificate present
No command-and-control addresses, network indicators or import-hash values were captured for this sample and none are asserted here. Defenders should hash-match the values above and, more importantly, hunt for the behavioral artifacts described below, since the Zeus configuration and dropped filenames differ from build to build.
Detection Heuristics
Antivirus and endpoint engines flag files like this through a combination of signature and heuristic logic. Signature families such as Zbot / Spyware.Zbot / Mal/Zbot match known code and structural patterns from the leaked Zeus codebase. Heuristic and machine-learning classifiers add several independent signals that apply well to this sample: an unsigned small executable, anomalous PE header flags, and 32-bit code masquerading as a benign utility all raise a binary's suspicion score. On execution, behavioral engines watch for the hallmark Zeus actions — process injection into explorer.exe or browser processes, API hooking for form grabbing, creation of autostart registry entries, and outbound beaconing — any of which is sufficient to quarantine the process. The generic .J variant tag itself indicates the object matched a heuristic cluster rather than a single fixed hash, meaning near-identical repacked copies will also be caught.
Digital Forensics
Investigators triaging a suspected Trojan.Zbot.J incident should focus on the artifacts that the Zeus family is publicly known to leave behind, while noting that this particular sandbox run logged zero registry modifications and zero file-write operations — an indication the sample did not detonate in the analysis environment. On a live, fully infected host you would typically hunt for:
- Files: a randomly named copy of the executable and an encrypted configuration/data file, historically staged under the user's AppData or a hidden folder in
%APPDATA%. Match the SHA-256 above where possible. - Registry: autostart entries under
Run/RunOncekeys pointing at the dropped binary (persistence). - Processes: unexpected injected threads inside
explorer.exe, browsers, or other trusted processes; unsigned modules loaded into signed processes. - Network: periodic outbound HTTP/HTTPS beacons to unfamiliar hosts (the specific endpoints are build-dependent and are not asserted here).
Because the analyzed object is unsigned and 32-bit, filtering endpoint telemetry for newly created unsigned x86 executables of a few tens of kilobytes is a productive starting point for scoping the blast radius.
Symptoms of Infection
Zeus/Zbot is built for stealth, so overt symptoms are often minimal. Warning signs users and admins may notice include: unexpected antivirus alerts naming Zbot or Trojan.Zbot.J; unfamiliar entries in Task Manager or at startup; browser sessions that behave oddly on banking sites (extra fields, unexpected re-authentication prompts, or redirects); unexplained account activity or fraudulent transactions; sluggish performance; and outbound network connections when the machine should be idle. Any confirmed detection should be treated as a full credential-compromise event.
How to Remove Trojan.Zbot.J
Because Zbot targets credentials, act quickly and, once cleaned, change passwords for banking, email and other sensitive accounts from a different, trusted device.
- Run a full malware scan. Install or update a reputable anti-malware tool such as SpyHunter and run a complete system scan (not a quick scan) so injected modules and dropped files are all detected. Quarantine and remove everything it flags, then reboot and re-scan to confirm the machine is clean.
- Reset affected browsers.
- Google Chrome: Settings → Reset settings → "Restore settings to their original defaults," then review Extensions and remove anything unfamiliar.
- Mozilla Firefox: Help → More troubleshooting information → "Refresh Firefox," then check Add-ons.
- Microsoft Edge: Settings → Reset settings → "Restore settings to their default values," then audit Extensions.
- Android: uninstall recently added or unknown apps, clear the affected browser's cache/data, and run a mobile security scan; if problems persist, back up data and perform a factory reset.
- Use Safe Mode for stubborn infections. Boot Windows into Safe Mode with Networking to stop the Trojan from auto-starting, then run the full anti-malware scan again.
- Manual cleanup (advanced users). End suspicious injected processes, delete the dropped executable and its configuration file from AppData, and remove the corresponding
Run/RunOnceautostart registry entries. Manual removal is error-prone; using the automated scanner above is safer and more thorough. - Post-remediation. Change all passwords, enable multi-factor authentication where possible, and monitor bank and email accounts for fraudulent activity.
Conclusion
Trojan.Zbot.J is a variant detection for the Zeus/Zbot banking-Trojan family — a mature, credential-stealing threat whose leaked source code keeps it relevant years after its debut. The sample profiled here is a small, unsigned 32-bit executable; while this specific object did not exhibit dynamic behavior in the sandbox, the family it belongs to is designed to quietly steal banking credentials and hand attackers remote control. Treat any Trojan.Zbot.J detection as a credential-theft incident: remove it with a full anti-malware scan, reset affected browsers, and rotate your passwords from a clean device.
Analysis Report
General information
| Family Name: | Trojan.Zbot.J |
|---|---|
| Signature status: | No Signature |
Known Samples
Known Samples
This section lists other file samples believed to be associated with this family.|
MD5:
4542cc147e9eee9e271dea72e1a58a93
SHA1:
f933688962af3999b11692a394837af8e5aa3ff5
SHA256:
6273E21CBAA594A4883876B0C58A9DEE0024185FA3C5349FF5C93249887A30B9
File Size:
45.06 KB, 45056 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
Show More
- 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 | Nokia |
| File Description | SerialServer MFC Application |
| File Version | 1, 3, 0, 1 |
| Internal Name | SerialServer |
| Legal Copyright | Copyright (C) 2001 Nokia Home Communications |
| Original Filename | SerialServerMFC.EXE |
| Product Name | SerialServerMFC Application |
| Product Version | 1, 3, 0, 1 |
File Traits
- x86
Block Information
Block Information
During analysis, EnigmaSoft breaks file samples into logical blocks for classification and comparison with other samples. Blocks can be used to generate malware detection rules and to group file samples into families based on shared source code, functionality and other distinguishing attributes and characteristics. This section lists a summary of this block data, as well as its classification by EnigmaSoft. A visual representation of the block data is also displayed, where available.| Total Blocks: | 143 |
|---|---|
| Potentially Malicious Blocks: | 2 |
| Whitelisted Blocks: | 96 |
| Unknown Blocks: | 45 |
Visual Map
? - Unknown Block
x - Potentially Malicious Block
