Malicious PDF — malware analysis report

Static analysis result for SHA-256 4f06d0045f9eb19c…

MALICIOUS

PDF

244.6 KB
MD5: a198a96a587d1756b0d1bbd97ee6d23d SHA-1: 0bfc3afc45106b4e988bc2d53a5d3e611b340c26 SHA-256: 4f06d0045f9eb19cb167156b1f03c07a882ec63857db1e0f70f0158032401885
390 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

This PDF file contains a critical PDF_LAUNCH heuristic indicating an attempt to execute cmd.exe. Further analysis reveals a VBScript-style decimal byte array that decodes to a PE payload, identified by ClamAV as Win.Trojan.Dropper-132 and Win.Trojan.Dropper-133. The embedded script also contains a launch action targeting cmd.exe, which is likely used to download and execute the second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

Heuristics 7

  • Launch action critical PDF_LAUNCH
    PDF contains a /Launch action whose target is an executable, URL, or UNC path — can start an external application
  • VBScript-style decimal byte array decodes to a PE payload critical PDF_VBS_DECIMAL_ARRAY_PE_PAYLOAD
    PDF comment text contains a VB/VBScript-style decimal byte array, such as c(077),c(090), that decodes to a verified Windows PE executable. The rule is gated on a comment-line Array(c(...)) assignment and a valid MZ/PE header to keep false positives low.
  • /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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_pdf_script_0003cc93.bin
32f6e505c97b7d536b3782480e57ed6170ef4a9b5960108d3f59bff91d44025f
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).
decimal_array_pdf_pe_00000229.exe
f9196dae2c4bd33d2e6f137fc17e0b65796cabe974b91932baabee205606ac69
embedded-pe PDF raw comment decimal-array PE payload at offset 0x229 34908 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.76, consistent with packed or encrypted content.