Malicious PDF — malware analysis report

Static analysis result for SHA-256 91cc522f3d5e4842…

MALICIOUS

PDF

77.7 KB Created: 2021-09-15 15:48:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 54a34ffba5ac86319dc3fc4ba1e4aa2c SHA-1: 18580c45e8b2020814d51a95dfb49422ec01c5d3 SHA-256: 91cc522f3d5e4842a7ff209c95e99c5c2fdc661dfdc35b982a662b71e8d44245
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF document flagged by multiple heuristics and a machine learning classifier as malicious. It contains numerous embedded URLs, many of which point to potentially malicious PDF files hosted on various domains. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and the sheer number of distinct hosts suggest a link farm or phishing campaign designed to redirect users to malicious content. While no scripts were explicitly extracted, the nature of the embedded URLs and the ClamAV detection (Pdf.Phishing.Trojan) strongly indicate a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

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://pizzeriadevita.it/userfiles/files/merojinigugakumubek.pdf In PDF document text
    • https://stpm-sa.com/userfiles/file/rekuwip.pdfIn PDF document text
    • http://qapoll.com/2015/vat/upload/files/karit.pdfIn PDF document text
    • http://ziepniekkalns.lv/wp-content/plugins/formcraft/file-upload/server/content/files/1613b47641d2f0---82003054202.pdfIn PDF document text
    • https://harshahometutors.com/uniformkontakt/userfiles/image/files/30054336588.pdfIn PDF document text
    • http://derp74.fooden.com/UserFiles/files/948297271.pdfIn PDF document text
    • http://didaconcept.com/admin/fckeditor/file/36632844349.pdfIn PDF document text
    • http://drtamerturan.com/file/bedogulalibofuma.pdfIn PDF document text
    • https://taiwancy.com/app/webroot/userfiles/files/videgebek.pdfIn PDF document text
    • http://hsaltsj.com/uploads/files/sekepapibazomotemijijo.pdfIn PDF document text
    • http://kool-house.com/upload/editor/file/63716616318.pdfIn PDF document text
    • http://market-oborudovanie.ru/upload/file/72492276996.pdfIn PDF document text
    • http://ncdesign.it/userfiles/files/dinedebeze.pdfIn PDF document text
    • http://kassa.pl/userfiles/file/robatuj.pdfIn PDF document text
    • https://adeptos.clevercloud.pt/images/items/files/nunugurumaxo.pdfIn PDF document text
    • http://eska-lift.ru/userfiles/file/18891951349.pdfIn PDF document text
    • http://nhungbaithuocnam.com/img-tvdl/files/41292349367.pdfIn PDF document text
    • http://abwhopewell.com/uploads/files/5759446671.pdfIn PDF document text
    • http://getdol.com/page_data/file/64289999632.pdfIn PDF document text
    • https://karapinler.com/calisma2/files/uploads/sitisar.pdfIn PDF document text
    • https://catwalkdogcome.com/editor_upload_image/file/vavisadatitovuluzizipa.pdfIn PDF document text
    • http://dispensapertutti.com/userfiles/files/zofofusegevixubivinil.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=kinemaster+pro+windows+10PDF 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_off0000c56a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC56A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000dd7c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD7C 20124 bytes
SHA-256: 4a9e3fe57551311b1cf2fee2c91bedd2aac0ac24e3179d36881d3e0473973718
font_02_sfnt_off0001112c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1112C 10756 bytes
SHA-256: 3a7bc737457ae2377f68ffa36b37b9204e247423d273ff72911224b3d62bdcb1

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