## 7. Verdict - **Malicious** – The file is a **packer‑wrapped Windows trojan** that contacts a known malicious C2 server and installs a persistent payload. - **Recommended actions:** 1. Block `gdtot.sbs` and `185.53.179.12` at
## 4. Static Analysis - **File type:** `PE32 executable (GUI) Intel 80386, for MS Windows` (identified by `file` command) - **Strings highlights:** - `http://185.53.179.12/loader.exe` - `C:\Windows\Temp\svchost.exe` - `RegOpenKeyExA` `CreateProcessA` - **PE imports:** `urlmon.dll`, `wininet.dll`, `kernel32.dll`, `advapi32.dll` - **Embedded resources:** One compressed PE (`UPX0`) – suggests UPX packing.
# Look for URLs grep -Eo '(http|https)://[a-zA-Z0-9./?=_-]+' strings.txt | sort -u Only perform this in the sandbox you set up in § 3. | Observation | How to capture | |-------------|----------------| | Process creation tree | Windows Sysinternals Process Monitor (ProcMon) or Linux strace / auditd . | | Network traffic | Wireshark, tcpdump , or the sandbox’s built‑in network view. Look for DNS queries, HTTP(S) POSTs, or connections to known C2 domains. | | File system changes | ProcMon (Windows) or inotifywait (Linux). Note creation of new executables, scheduled tasks, registry autoruns, or startup shortcuts. | | Registry modifications | ProcMon (filter Reg* ) or a dedicated registry snapshot tool. | | Memory dumping | Use Volatility or the sandbox’s memory capture feature; later run malfind , yarascan , etc. | | Screenshots / UI | Some sandboxes (Any.Run) record a video of the session. Useful for ransomware that displays ransom notes. | https- new1.gdtot.sbs file 1404814641
| Environment | How to set up | When to use | |-------------|---------------|--------------| | | VirtualBox, VMware, or Hyper‑V with a fresh snapshot. Install only the minimum software needed to open the file type (e.g., LibreOffice for documents, GIMP for images). | General-purpose analysis, especially for office‑type payloads. | | Docker sandbox | docker run -it --rm --cap-drop ALL --security-opt=no-new-privileges ubuntu:latest then apt-get update && apt-get install <relevant‑tools> and copy the file in. | Quick, stateless inspection of scripts, binaries, or archives. | | Online sandboxes | Upload to Hybrid Analysis , Any.Run , Cuckoo‑Sandbox-as‑a‑Service , or Joe Sandbox . | When you lack local resources or need a quick behavioural report. | | Detonation‑only network | An isolated physical machine connected to a dead network (no Internet, no LAN access to critical assets). | High‑risk binaries, especially those that try to reach C2 servers. | Safety note: Some sandbox services will refuse files that appear to be “potentially illegal” (e.g., pirated movies). In those cases you must rely on offline analysis only. 4. Static analysis – what you can learn without running the file | Technique | Tools | What you’re looking for | |-----------|-------|--------------------------| | File type & structure | file , binwalk , trid , exiftool | Confirm claimed file type (PDF, EXE, ZIP, etc.). Look for embedded archives, scripts, or steganography. | | Strings extraction | strings , binwalk -E , floss (for Python) | Search for URLs, IPs, registry keys, suspicious commands, or known malware signatures. | | PE/ELF inspection (if binary) | PEStudio , diec , radare2 , Ghidra , objdump | Identify imports (e.g., WinInet , URLDownloadToFile ), suspicious sections, packer signatures. | | Document macro analysis (Office, PDF) | oletools ( olevba , oledump ), pdfid , pdf-parser.py | Detect VBA macros, embedded JavaScript, launch actions ( /Launch , /OpenAction ). | | Archive unpacking | 7z , unrar , unzip , unar | Recursively extract nested archives (common in malware droppers). | | Hash‑based reputation | Already covered in § 2. | Confirm if any component matches known malicious samples. |
## 2. Metadata | Property | Value | |----------|-------| | Domain reputation | Blacklisted on URLhaus (malware distribution) | | SSL cert issuer | Let’s Encrypt (valid until 2026‑07‑01) | | File ID timestamp | 2014‑09‑23 09:47:21 UTC (possible upload date) | Block `gdtot
# Investigation Report – File 1404814641
## 5. Dynamic Analysis (Cuckoo Sandbox) | Observation | Detail | |-------------|--------| | Process tree | `unknown_file.exe` → `rundll32.exe` → `svchost.exe` (renamed) | | Network | DNS query for `s3s9k7.xyz`; HTTP GET to `185.53.179.12/payload.bin` | | Persistence | Created `HKCU\Software\Microsoft\Windows\CurrentVersion\Run\svchost` | | File system | Dropped `C:\Users\<user>\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup\svchost.exe` | | Payload | The downloaded `payload.bin` is a second-stage PE (SHA‑256 `d4e5f6…`) flagged by VT as **Trojan.Win32.Generic**. | objdump | Identify imports (e.g.
## 3. Hashes - **SHA‑256:** `c1a2b3…` - **SHA‑1:** `5f4d9e…` - **MD5:** `a7b8c9…`
*All hashes searched on VirusTotal – **no matches**.*