Malicious PDF — malware analysis report

Static analysis result for SHA-256 73a50bb3b57a654e…

MALICIOUS

PDF

38.0 KB Created: 2020-04-12 03:48:19 +03:00 Authoring application: wkhtmltopdf 0.12.1.4 (via Qt 4.8.6)
MD5: 0ade581107e9d7cd84a58afca9f149b9 SHA-1: 26b98d38b74795ac11af0e9628e2d497af30ba47 SHA-256: 73a50bb3b57a654ed23a655c934f6df2585aeb71915a4e9954c45ca4c58f806e
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF document contains a large number of embedded links to external websites, many of which appear to be part of a link farm designed to manipulate search engine results. The document body, though heavily obfuscated, contains text related to counting exercises for primary school children, suggesting a lure to attract unsuspecting users. The ML classifier strongly indicated maliciousness, and the sheer volume of external links points towards a malicious intent, likely to redirect users to phishing or malware hosting sites.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

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://mmhac.com/uploads/1/3/1/4/131453623/131453623.html#ejercicios+de+problemas+de+conteo+para+ni%C3%B1os+de+primaria
    • http://llanemusic.com/uploads/1/3/1/1/131164481/286901.pdf
    • http://busybeesoundstudio.com/uploads/1/3/0/6/130604152/3d38769ae.pdf
    • http://mayancateringftcollins.com/uploads/1/3/0/4/130483045/situwuki.pdf
    • http://httpdoctorblues.com/uploads/1/3/1/4/131453512/e03b1ce851.pdf
    • http://stlhomeproperties.com/uploads/1/3/0/7/130739095/e98aecf948db20a.pdf
    • http://idialysis.org/uploads/1/3/0/4/130489157/jupumiwuzajukiwaru.pdf
    • http://sandboxlogin.com/uploads/1/3/1/1/131164109/9758137.pdf
    • http://creightonwebdesign.com/uploads/1/3/0/2/130288430/zozudi.pdf
    • http://hilotmassage.pl/uploads/1/3/0/3/130379162/5504621.pdf
    • http://blueribbonsquare.com/uploads/1/3/0/3/130313657/gepizulaf-nefawupazemisas-vujoburo.pdf
    • http://rijschooldronten.nl/uploads/1/3/0/8/130873738/1737378.pdf
    • http://tr3realestate.net/uploads/1/3/0/6/130621958/gudezamimedufi.pdf
    • http://prodbyedmond.com/uploads/1/3/0/5/130588352/2234251.pdf
    • http://mattpaino.com/uploads/1/3/0/6/130604766/mizebexarokagi_xajatujeb.pdf
    • http://phamilyphirstmanagement.org/uploads/1/3/0/7/130776776/divolokigopekib.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_off0000692c.bin
b825e6caaeb1fb7679256de9906172af2c1033c6884e3c7b304f9ea6d6427f91		 pdf-font-stream PDF embedded font (sfnt) at offset 0x692C 8672 bytes

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