Malicious PDF — malware analysis report

Static analysis result for SHA-256 76d3310e659cfde5…

MALICIOUS

PDF

35.5 KB Created: 2020-06-14 08:39:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2020-09-24
MD5: d50852c604b4a290e85733381e0f0dcf SHA-1: 15d9be9eb5407a1092bdc3242f6ecf536cec292b SHA-256: 76d3310e659cfde55bc0ebded89f0efc7a18aa92a2c9c07b7ef12d328febaea6
96 Risk Score

Malware Insights

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

The PDF document presents itself as an academic exam to lure users to a large number of external URLs, many of which are likely part of a link farm for SEO manipulation or malware distribution. The ML classifier strongly indicated maliciousness, and the embedded URLs suggest a phishing or credential harvesting attempt. No scripts were extracted, but the PDF structure and numerous external links are highly suspicious.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

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://exsightcapital.com/uploads/1/3/0/8/130874134/130874134.html#examen+de+espa%25C3%25B1ol+segundo+grado+de+secundaria PDF link annotation
    • http://13k.undesirable.us/uploads/1/3/0/3/130323337/3b8f18b1.pdfIn PDF document text
    • http://scoreadog.com/uploads/1/3/0/3/130323127/jazofome.pdfIn PDF document text
    • http://advokathagerup.com/uploads/1/3/1/4/131453222/keral-beniwu.pdfIn PDF document text
    • http://untamedappetites.com/uploads/1/3/1/4/131454762/wezikuguj-pupilumef-vatol.pdfIn PDF document text
    • http://mta-sts.mail.meetthemessenger.com/uploads/1/3/0/9/130969221/2966009.pdfIn PDF document text
    • http://vpn.stmartindp.com/uploads/1/3/0/6/130620972/fowosopa-ledepotutawa-nawuwimo-lofuziro.pdfIn PDF document text
    • http://concussionhealthsummit.com/uploads/1/3/1/4/131453455/tewuk.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://bugigos.files.wordpress.com/2020/06/38598874907.pdfIn PDF document text
    • https://gasoxof.files.wordpress.com/2020/06/71386186244.pdfIn PDF document text
    • https://lunudosur.files.wordpress.com/2020/06/17857727550.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00005a5c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x5A5C 11708 bytes
SHA-256: b73dfef5809b860e36ce48a1e77be02180b88e1d325fdff2ffd4d7adf2d8bf8b