Malicious PDF — malware analysis report

Static analysis result for SHA-256 3b9d71d464bf9687…

MALICIOUS

PDF

136.8 KB Created: 2011-09-08 05:03:17 Authoring application: FPDF 1.6
MD5: 05cdc58eb8d872b0703b5c5f771b20dd SHA-1: d3b6e16c233ddb0fe5da90c8bf250381c77efbfe SHA-256: 3b9d71d464bf968717ff40044fcf0cf32bbb51e5249a9a0b7fe9c0956b2ada75
108 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File T1566.002 Spearphishing Attachment

The PDF was flagged by a machine learning classifier with high confidence and also detected by ClamAV as Pdf.Exploit.Agent-36874. The presence of an XFA form and an AcroForm button with an action trigger suggests an attempt to exploit PDF vulnerabilities. The ML classifier's high score and the ClamAV detection strongly indicate a malicious exploit embedded within the PDF, likely designed to download and execute a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

Heuristics 4

  • ClamAV: Pdf.Exploit.Agent-36874 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36874
  • XFA form low PDF_XFA
    PDF uses XML Forms Architecture — can contain script logic
  • AcroForm button with action trigger low PDF_ACROFORM_BUTTON
    PDF contains a /Btn form field together with a SubmitForm/URI/Launch/JS trigger — this is the building block of fake 'Download' or 'Open' button overlays used in PDF phishing lures
  • Suspicious extracted artifact info 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
stream_001_off000008ed.bin
293bb51b3a8d48be95182e1e5c640c331d99aa087ec313f41cf87f231f716f1d
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x8ED 1425 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).