Malicious PDF — malware analysis report

Static analysis result for SHA-256 f81cd4b476e228fe…

MALICIOUS

PDF

81.1 KB Created: 2021-09-13 19:29:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 0c9691f9518b75bceb18c324fdd7d094 SHA-1: f4420bbebad22e79231973b64118f2a99e6a1e1a SHA-256: f81cd4b476e228fe0e2ffab15ca64ab377261d3e021a64475902bdd0e1c2c4a5
154 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains a high number of external links pointing to other PDFs, characteristic of a link farm designed to obscure malicious intent. The 'PDF_SEO_DISPOSABLE_LINK_FARM' heuristic and the presence of numerous unknown URLs strongly suggest a phishing or malware distribution attempt. The ClamAV detection further confirms the malicious nature of the file.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 7

  • 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.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://sure2trips.com/bot/ckfinder/uf/files/bifevavivuvirojo.pdf In PDF document text
    • http://test-immo.com/file/88906903807.pdfIn PDF document text
    • http://ttccid.com/userfiles/file/mukogapiz.pdfIn PDF document text
    • https://nulifeus.com/~nulife/userfiles/file/zenikibapo.pdfIn PDF document text
    • http://nebovsem.ru/app/webroot/files/files/vitipur.pdfIn PDF document text
    • https://apc-algercentre.dz/ckfinder/userfiles/files/12695750711.pdfIn PDF document text
    • http://benthanhsgfarm.com/images/uploads/files/30341548155.pdfIn PDF document text
    • https://mysilo.com/upload/ckfinder/files/70319210574.pdfIn PDF document text
    • https://xaydungdonggia.com/app/webroot/files/images/pages/files/laludekinaxefurezitoj.pdfIn PDF document text
    • http://azseal.net/uploads/userfiles/file/lifagosemavaro.pdfIn PDF document text
    • https://johanbjerke.se/userfiles/file/dogazepulekep.pdfIn PDF document text
    • https://ms02bet.com/contents/files/toranej.pdfIn PDF document text
    • https://kiofruits.com/admin/uploads/files/788394388.pdfIn PDF document text
    • http://mrpennarak.com/user_file/file/foperofade.pdfIn PDF document text
    • https://guineaservicesproviders.com/gsp/files/kaxel.pdfIn PDF document text
    • https://www.mclarenpress.com/wp-content/plugins/formcraft/file-upload/server/content/files/161378197c8091---fofotusasuxofebomubilil.pdfIn PDF document text
    • http://mbfeed.vn/upload/files/wibapizimu.pdfIn PDF document text
    • http://www.haztartasigepszakuzlet.hu/pics/file/72963167292.pdfIn PDF document text
    • http://cserepakciok.hu/xdata/file/59773809987.pdfIn PDF document text
    • http://jmyhship.com/uploadfile/files/vodalodal.pdfIn PDF document text
    • http://marathon-gexin.com/Uploadfiles/files/39870574405.pdfIn PDF document text
    • http://dydlhx.com/upfiles/file///pedamuzuju.pdfIn PDF document text
    • http://kaus21.com/userData/board/file/tinifupobewik.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/S30rS-6n6vg/uplcv?utm_term=how+can+i+see+profile+visits+on+instagramPDF 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_off0000d4b5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD4B5 10964 bytes
SHA-256: 68cd1aa2009074767aa97f417b36cd9f1e8645b6f075b0a65e434bf394947cc7
font_01_sfnt_off0000ee2b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE2B 18668 bytes
SHA-256: 1383f513bd87073cda1e6e7bc85246cfec344f6e6048709d95222a963b7daab4
font_02_sfnt_off00011e60.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E60 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1