Malicious PDF — malware analysis report

Static analysis result for SHA-256 85b23b78df4e77a4…

MALICIOUS

PDF

98.4 KB Created: 2021-09-14 01:21:35 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-02
MD5: b2087f7fcfed9d8278e594ab93e55e79 SHA-1: 2e3c45176dd10481642a830a82266b451945c445 SHA-256: 85b23b78df4e77a465e04723daae9f8cc189fcfbbfddc3b8e624493f44e9d4a4
126 Risk Score

Malware Insights

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

The file was detected as malicious by ML classifiers and ClamAV, specifically flagged as a phishing trojan. It contains numerous embedded URLs, many pointing to PDF files hosted on various domains, indicating a link farm or content distribution network. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, suggesting the PDF is part of a scheme to manipulate search engine results or distribute content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

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 http://dichvu12h.net/userfiles/file/34476823176.pdf In PDF document text
    • http://agedwedfjtj.pretty-match.com/upload/files/kadidobijazoj.pdfIn PDF document text
    • http://otelm4b.ru/admin/ckfinder/userfiles/files/90400453533.pdfIn PDF document text
    • http://acmemask.com/upfiles/editor/files/77252548491.pdfIn PDF document text
    • http://madmojo.com/fckupload/file/fitopapowaduzebis.pdfIn PDF document text
    • https://vico-domrep.com/ckfinder/userfiles/files/50425916048.pdfIn PDF document text
    • http://digifast.cz/userfiles/22627359763.pdfIn PDF document text
    • http://www.urbanwaterways.info/files/45407302406.pdfIn PDF document text
    • http://splhardware.com/UploadFile/file/2021090619385073499.pdfIn PDF document text
    • https://pinkrali.com/calisma2/files/uploads/20876916989.pdfIn PDF document text
    • http://planet-for-events.de/userfiles/file/daxusadoxesuvejobesekuko.pdfIn PDF document text
    • https://xn--80aaa1anac6cg.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/46dc7361f7f1ae86b39c14daca70c01c/64173676078.pdfIn PDF document text
    • http://alpha-cp.com/userfiles/file/66736618638.pdfIn PDF document text
    • http://centrlita.ru/archive/image/file/18658315651.pdfIn PDF document text
    • http://kastely-vacduka.hu/fileok/file/wituku.pdfIn PDF document text
    • http://lienming-rubber.com/uploads/files/202109071106256453.pdfIn PDF document text
    • http://stphilomenaonline.org/userfiles/file/benedebumevelam.pdfIn PDF document text
    • https://leuphuotcamap.com/uploads/image/files/fugilededoramukovoradapu.pdfIn PDF document text
    • http://grandinhr.eu/images/user/file/zuvemitufilo.pdfIn PDF document text
    • https://doellefjelde-mussemarked.dk/images/newsmail/file/14891909848.pdfIn PDF document text
    • http://olddieselparts.com/ckfinder/userfiles/files/botibamosatoxebugemikazi.pdfIn PDF document text
    • https://milsagliksen.org/upload/ckfinder/files/kajixoponevirakezofag.pdfIn PDF document text
    • http://tourister.kr/userfiles/file/favelaxezesigir.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1xuhb7AK25c/uplcv?utm_term=unblocked+car+games+66PDF link annotation
    • 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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00011814.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11814 19388 bytes
SHA-256: fbd885b15e88b8d30c335addb079460aa910ee5b7a2da13b32d0923b685368e0
font_01_sfnt_off00014af4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14AF4 10928 bytes
SHA-256: 3fa66536223060eb6e9da8a01c79d11dc587dba44f2e71a864aafa0c263184ef
font_02_sfnt_off00016411.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16411 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1