Malicious PDF — malware analysis report

Static analysis result for SHA-256 85a53bdfb4184a3a…

MALICIOUS

PDF

80.6 KB Created: 2021-09-08 07:41:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: afbb7447248ddd778eefeab7d81d3af7 SHA-1: e383fd7f90f4c2f192acb190675a7c46b0dba8a5 SHA-256: 85a53bdfb4184a3ae5fc2e2261cbdd7c66c6eb7348a2cecafa8c910a506589ad
156 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous embedded URLs, many of which point to compromised CMS uploads or disposable hosting, forming a link farm. While no scripts were explicitly extracted, the PDF structure and the presence of external links suggest it is designed to redirect users, likely to a phishing page or a download site for further payloads. The `wkhtmltopdf` authoring application is noted, but does not directly indicate maliciousness.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://radfordhsclassof1970.com/clients/878146/File/vefodixupiriz.pdf In PDF document text
    • http://www.espace-hotelier.com/ckfinder/userfiles/files/51014330437.pdfIn PDF document text
    • http://slenderclub.cz/ckfinder/userfiles/files/dirobazoloxa.pdfIn PDF document text
    • http://activesolutionelectric.com/images/file/4505643885.pdfIn PDF document text
    • http://parcfamilyreunion.com/clients/b/b3/b3ae52aef0329bb57e848b27182677c8/File/84012154223.pdfIn PDF document text
    • https://agroadvanced.com/app/webroot/newsletters/editor/files/55176250153.pdfIn PDF document text
    • http://emeraldcovepartners.com/_data/images/file/wedarutinisu.pdfIn PDF document text
    • https://newsru.md/upload/userfiles/files/1012905350.pdfIn PDF document text
    • http://normel.org/files/upload/file/45263913056.pdfIn PDF document text
    • http://msci.com.ng/wp-content/plugins/formcraft/file-upload/server/content/files/1611884d5b93dd---15153703333.pdfIn PDF document text
    • https://xn--80aaaglcftt5alesfkk7f.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/aeb33f48a9db0809beb195ba8d1ac4a3/winen.pdfIn PDF document text
    • https://atcotourismtravel.com/userfiles/file/2511321093.pdfIn PDF document text
    • https://n95america.com/wp-content/plugins/super-forms/uploads/php/files/f4544224dab5f9d698b6fe98ea4ee95b/8244968369.pdfIn PDF document text
    • http://arredamenticucinesiciliane.it/userfiles/files/luvilapuretonadexa.pdfIn PDF document text
    • http://www.combatsim.eu/wp-content/plugins/formcraft/file-upload/server/content/files/160b0cc51195cd---93991464174.pdfIn PDF document text
    • https://clubsportedinburgh.org/userfiles/files/velelegaf.pdfIn PDF document text
    • http://htwy.com/upload/file/tuxekod.pdfIn PDF document text
    • https://amezdigital.com/wp-content/plugins/super-forms/uploads/php/files/d62c08b55da7c313be4aff242a0e9d04/guzogajomatididi.pdfIn PDF document text
    • https://dolaodong.com/userfiles/file/balolezojopiwana.pdfIn PDF document text
    • http://dailyxedayhang.com/userfiles/files/90387346019.pdfIn PDF document text
    • https://formapolis.it/wp-content/plugins/super-forms/uploads/php/files/25416375d8a0f0c88c877efb412867d3/jakofefepitiparijivofox.pdfIn PDF document text
    • http://konditsionery-reutov.ru/upload_picture/file/97883320131.pdfIn PDF document text
    • https://lllk.ru/wp-content/plugins/super-forms/uploads/php/files/b45db47167fb48bd19a132272db08e31/5775082301.pdfIn PDF document text
    • https://www.sir.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1607f3b974f6cf---37207407001.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/LPIa9PGmDLg/uplcv?utm_term=wordly+wise+book+3+lesson+5+pdfPDF 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_off0000d5d5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD5D5 17948 bytes
SHA-256: e68b49c9306796a2b419174b7037815103d25302219918476c7832e0bbbcd5ec
font_01_sfnt_off000103b3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x103B3 10960 bytes
SHA-256: 50b2e8075f047bfe2c750a56da4061852afdb13d62a7682731a55f18cf37bf6a
font_02_sfnt_off00011d18.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11D18 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1