Malicious PDF — malware analysis report

Static analysis result for SHA-256 c21f7cc5dfec8950…

MALICIOUS

PDF

68.3 KB Created: 2021-09-25 16:52:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-07
MD5: 9222a1d552bf3a13d83828c4ab963138 SHA-1: c088952f8a1f1035ef9f48d2a86a85149ef0c998 SHA-256: c21f7cc5dfec8950cb491e3c0264e17821abcee9086d9bf171be10033a3a7da8
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF document contains numerous embedded URLs, many of which point to domains associated with link farms and disposable hosting, as indicated by the PDF_SEO_DISPOSABLE_LINK_FARM heuristic. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or distributing further malware. Although no scripts were explicitly extracted, the presence of numerous external URIs suggests the document's primary purpose is to redirect users to potentially harmful websites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9957

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://infrive.ru/uplcv?utm_term=tube+med+download PDF link annotation
    • http://dydlhx.com/upfiles/file///9543163021.pdfIn PDF document text
    • https://bulgariapools.com/contents/files/xiwogivusuf.pdfIn PDF document text
    • http://zhihepvb.com/upload/ckimg/files/202109151831256259.pdfIn PDF document text
    • http://gps-tw.com/CKEdit/upload/files/xekutelediwutewejijoxop.pdfIn PDF document text
    • http://romanakladatelstvi.cz/userfiles/file/44709575240.pdfIn PDF document text
    • https://www.pollackmihalyiskola.hu/ckfinder/userfiles/files/vodidebamufajik.pdfIn PDF document text
    • https://gcr.goldcrownresort.com/magazine_files/files/rerunaziwizisaz.pdfIn PDF document text
    • http://awards.nl/img/cms/file/36669808757.pdfIn PDF document text
    • http://kool-house.com/upload/editor/file/23733181665.pdfIn PDF document text
    • http://solarwindependence.com/ckfinder/userfiles/files/xotimidaxelegiwe.pdfIn PDF document text
    • http://studiogiovannone.com/userfiles/files/zabanisedunewevetu.pdfIn PDF document text
    • http://frigotechreina.com/userfiles/files/77842931677.pdfIn PDF document text
    • https://presstone.hu/userfiles/file/jeforilogerulobujuwul.pdfIn PDF document text
    • http://eot.mn/uploads/userfiles/files/34159902349.pdfIn PDF document text
    • http://xn--elementy-zczne-kwb98g.pl/media/file/megogimokenegumonomuri.pdfIn PDF document text
    • http://thrifthelp.com/flash/thrifthelp.com/file/zefetuxatuzuda.pdfIn PDF document text
    • https://dnmpaint.com/sdcc/images/file/93378516679.pdfIn PDF document text
    • http://ildongwire.com/userfiles/file/8192003700.pdfIn PDF document text
    • http://potlista.com/file/files/vipoleketo.pdfIn PDF document text
    • http://admio.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1613940c3d74fb---46951969280.pdfIn PDF document text
    • http://thienminhgroup.com/uploads/userfiles/file/likujodeg.pdfIn PDF document text
    • http://twfbs.com/ckfinder/userfiles/files/9427882924.pdfIn PDF document text
    • http://freestyler.cz/img/file/14110806759.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://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_off0000acf0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xACF0 15216 bytes
SHA-256: 3f51716ea4a2536f274973446268c701d101ca55f5115ca0faf2fa797c42a8c7
font_01_sfnt_off0000d393.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD393 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000ebaa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEBAA 10240 bytes
SHA-256: 6aae1f9271ac55b509bf40c4b8727e2483894937d64ee94a1729c0fec617f84e