Malicious PDF — malware analysis report

Static analysis result for SHA-256 6bbc0461607f856f…

MALICIOUS

PDF

5.6 KB First seen: 2013-01-23
MD5: dbb21e26d4dcfb7691849a22795c9035 SHA-1: 14f52c3f998a23a98e52f20c2c4b16ab42648851 SHA-256: 6bbc0461607f856f545d7feee1b598911642620fd5270d43696fbb88bab47743
72 Risk Score

Malware Insights

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

The sample is a PDF file identified as malicious by an ML classifier. It contains a malformed stream with embedded JavaScript, indicated by the 'PDF_MALFORMED_EXPLOIT_STREAM_LENGTH' and 'PDF_EMBEDDED_SCRIPT_PAYLOAD' heuristics. This script is likely designed to download and execute a secondary payload, as suggested by the embedded file artifact. The benign URLs present do not detract from the malicious nature indicated by the heuristics and ML score.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 6

  • 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.
  • 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.
  • 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 0x78 5049 bytes
SHA-256: 8dec16ed9ed24763de96371fd4a84bec8d707c17a18702c5ab56edb8302a9a02
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 long base64-like blob(s).

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