Malicious PDF — malware analysis report

Static analysis result for SHA-256 4c4df829f0f9aa57…

MALICIOUS

PDF

136.8 KB Created: 2011-09-08 05:03:17 Authoring application: FPDF 1.6
MD5: ac65420e07041a72c930842d9ab8091b SHA-1: 20a9d3fa69bb0e44d210c1c327bf2a96cd66f1d7 SHA-256: 4c4df829f0f9aa57a361753be55bf86931c9e3f17f14208a08c2b6860efd4187
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 and ClamAV as malicious, specifically detecting it as Pdf.Exploit.Agent-36874. The presence of an XFA form and an AcroForm button with an action trigger suggests an attempt to exploit a PDF vulnerability. An embedded artifact, a decompressed PDF stream, was also identified as suspicious. The document body contains obfuscated text, typical of exploit-laden PDFs.

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
bae9199c07c464f74196d58f5824d331e1f0e02551dc1ff0cce6bf23dcd59c99
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x8ED 1429 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).