Malicious PDF — malware analysis report

Static analysis result for SHA-256 4fc81991dd789bdd…

MALICIOUS

PDF

244.6 KB
MD5: c9c686ce9e35128bbdd52001459b6c1f SHA-1: d0c730cc0337111cde345ac96fcf70bd4657d3d5 SHA-256: 4fc81991dd789bdd23c2500cdf65a7d919d4ed2664b1df7ef911131bb3e5a492
330 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File

This PDF document contains an embedded script payload, indicated by multiple critical heuristic firings including PDF_LAUNCH and PDF_LAUNCH_COMMAND. The script is designed to execute cmd.exe with a command that likely initializes a FileSystemObject, suggesting it's part of a dropper or downloader mechanism. The ClamAV detections further confirm its malicious nature as a trojan dropper.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

Heuristics 6

  • Launch action critical PDF_LAUNCH
    PDF contains a /Launch action whose target is an executable, URL, or UNC path — can start an external application
  • /Launch action target: cmd.exe critical PDF_LAUNCH_COMMAND
    PDF /Launch action specifies an executable target with parameters '/c echo Set fso=CreateObject("Scripting.FileSystemObject"' — references a known-dangerous executable (cmd, PowerShell, etc.).
  • ClamAV: Win.Trojan.Dropper-132 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Trojan.Dropper-132
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • Embedded script payload in PDF stream high PDF_EMBEDDED_SCRIPT_PAYLOAD
    PDF stream bytes contain script execution markers such as ActiveXObject/CreateObject, WScript.Shell, PowerShell, or shell-exec primitives. This is stronger than ordinary PDF JavaScript because it indicates a staged external script payload hidden in stream bytes.
  • Suspicious extracted artifact medium EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_pdf_script_0003cc93.bin
9818e31f15457be463e77fddcc7517da95f8fa61280785d97180dcdf9801ab59
pdf-embedded-script PDF raw stream script payload at offset 0x3CC93 248958 bytes
Detection
ClamAV: Win.Trojan.Dropper-133
Obfuscation or payload: likely
Carved artifact contains 2 shell/COM execution token(s).