Malicious PDF — malware analysis report

Static analysis result for SHA-256 dcb1378742f9da57…

MALICIOUS

PDF

31.8 KB Created: 2020-04-19 01:57:07 +03:00 Authoring application: wkhtmltopdf 0.12.1.4 (via Qt 4.8.6)
MD5: d9d3d81c02fe3b9d216928f1d1bd0416 SHA-1: 59a79a0922e23b9ef23f41d94349485a5a1c212a SHA-256: dcb1378742f9da5763092dcd3d3be12cc67980b69aab2d155f023ddcfa03f215
94 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains a large number of external links to various domains, identified by the PDF_SEO_LINK_FARM heuristic. These links point to PDF files with numeric slugs, suggesting a link farm or SEO abuse tactic. The ML classifier also flagged this PDF as malicious with high confidence. The document body contains a reference to 'Coursera robotics perception quiz answers', likely a lure to entice users to click the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9986

Heuristics 4

  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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://myhoneybeetherapy.org/uploads/1/3/1/3/131382395/131382395.html#coursera+robotics+perception+quiz+answers
    • http://bubblebandage.com/uploads/1/3/0/5/130551782/kimerobofo-pegikexate-jusutof.pdf
    • http://battlegroundstate.com/uploads/1/3/1/3/131383945/mununawexazib.pdf
    • http://whiskeydarling.com/uploads/1/3/0/4/130436222/sirekuvobafor.pdf
    • http://pinkypromiseonline.com/uploads/1/3/0/7/130739764/759922.pdf
    • http://lausdeocapitalinvestmentsinc.com/uploads/1/3/1/0/131070858/6437254.pdf
    • http://ccshamilton.com/uploads/1/3/1/6/131606365/a46f87ec433d0.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000553d.bin
d107768ad8f0d49b849cfc57ba38b7c4314e305e8083a02d4f39c6c987f889ff		 pdf-font-stream PDF embedded font (sfnt) at offset 0x553D 7764 bytes

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