Malicious PDF — malware analysis report

Static analysis result for SHA-256 66b84f2f7c0c8399…

MALICIOUS

PDF

99.7 KB First seen: 2015-09-15
MD5: 0ec946ab69a4028deb8f15bcb05dd06b SHA-1: 8e49a663f9453b9559b209f2adc75690d76db168 SHA-256: 66b84f2f7c0c83998162877b14fac3e84268e30d7a078a54df6c6ca0acaa51fd
70 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The PDF sample contains malformed active content and an embedded script payload, strongly indicating an exploit attempt. The ML classifier also flagged it with high confidence. While the embedded URLs are benign, the presence of an exploit stream and embedded script suggests the file is designed to execute malicious code, likely a downloader for further stages. The XFA form and embedded file heuristics further support this conclusion.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 5

  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • XFA form low PDF_XFA
    PDF uses XML Forms Architecture — can contain script logic
  • Embedded script payload in PDF stream info PDF_EMBEDDED_SCRIPT_PAYLOAD
    PDF stream bytes contain an HTML/XFA <script> tag without accompanying Windows shell-execution primitives — common in accessible XFA forms but worth surfacing for analyst review.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://ns.adobe.com/xdp/ In PDF document text
    • http://www.xfa.org/schema/xfa-template/2.5/In PDF document text
    • http://www.xfa.org/schema/xfa-data/1.0/In PDF document text

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_file_obj0008.bin pdf-embedded-file PDF EmbeddedFile object 8 at offset 0xC6 101380 bytes
SHA-256: 2196938afbf695a5d8d5e3e6dc8e14d97e2a1d42a4a8be9ebc17fb2466db094c

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