Malicious PDF — malware analysis report

Static analysis result for SHA-256 83ced562a25e416f…

MALICIOUS

PDF

70.2 KB Created: 2021-04-08 12:24:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: 9504f49492224f165fef86ccfd92634b SHA-1: 007c4895be622c6848f45955e24a973a7c0b6a13 SHA-256: 83ced562a25e416fea1cedca4ddbed5ecc3afc407cd6d93363d493d1e660a6c2
126 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which point to disposable hosting and are likely part of a link farm designed to obscure the true malicious destination. The document body, though heavily obfuscated, suggests a lure related to a 'college biology textbook'. No scripts were extracted, but the presence of multiple unknown URLs indicates a likely attempt to redirect the user to a malicious site or download a secondary payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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 https://www.a1touchsolution.nl/sites/default/files/xofarazenufokedakuzos.pdf In PDF document text
    • http://www.grotekeukens.be/sites/default/files/webform/gmawards2018/98751459569.pdfIn PDF document text
    • https://www.blplegal.com/sites/default/files/webform/pifijolaj.pdfIn PDF document text
    • http://seiary.com/sites/default/files/webform/rec/55418097166.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/vewamilobofesiwukor.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/55178968397.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/zomosazufexebale.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/51762260361.pdfIn PDF document text
    • https://www.uts.cw/sites/default/files/webform/suvexaxobufakup.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • http://feedproxy.google.com/~r/Uplcv/~3/3vuEKuznOb8/uplcv?utm_term=college+biology+textbook+by+idodo+umeh+pdfPDF link annotation
    • https://printandmail.princeton.edu/system/files/webform/54002061309.pdfIn PDF document text
    • https://printandmail.princeton.edu/system/files/webform/26360011081.pdfIn PDF document text
    • https://umatter.princeton.edu/system/files/webform/requests/tutoturabawukaxubudevodor.pdfIn PDF document text
    • https://www.healthdata.org/sites/default/files/resumes/mevupuxapiledowitire.pdfIn PDF document text
    • https://gradfutures.princeton.edu/system/files/webform/xafuzekimizitigemuseli.pdfIn PDF document text
    • https://lib.asu.edu/system/files/webform/61431168480.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c89b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC89B 5144 bytes
SHA-256: df561ab628f015008c13d93bb11a62fbb3031de40ac2e2454dcc7aa179f50539
font_01_sfnt_off0000da36.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA36 10372 bytes
SHA-256: db8c44cc1c54a2b8ac4256898ecba6e764d94e550ad40615ebc0d9112c33d3f4
font_02_sfnt_off0000fd25.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD25 4324 bytes
SHA-256: b50a2106bf82917db0cd3cf88f63c5e8cc3298b343ace5cffc591b35df33d24c

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