Malicious PDF — malware analysis report

Static analysis result for SHA-256 dbd94331ac28c4eb…

MALICIOUS

PDF

71.7 KB Created: 2021-09-30 22:48:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: a715cf82abcddc59f2b79b394fc0525c SHA-1: 2776521e59b845e62c0d40bf92eeee3ec58a6187 SHA-256: dbd94331ac28c4eb24f04fed8fcd11bc2f405b0d946c01759dc8275a2bcea49c
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and by an ML classifier as malicious. It contains numerous embedded URLs, many pointing to compromised websites or disposable hosting, suggesting a link farm designed to redirect users to malicious content. The heuristic PDF_SEO_DISPOSABLE_LINK_FARM specifically indicates this pattern. While no scripts were explicitly extracted, the nature of the embedded URLs and the overall detection suggest a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 https://archism.ru/uplcv?utm_term=walking+dead+season+11+episode+19
    • http://www.sm.ac.th/ckfinder/userfiles/files/81845907924.pdf
    • http://metabolit.ru/files/file/52516760705.pdf
    • https://phnews.ro/files/file/dibotemokotupak.pdf
    • http://ediliziaunoaventi.com/userfiles/files/75940238031.pdf
    • https://pqclass.kr/imgs/file/puberonikilasunevigerifik.pdf
    • http://sprinter-lab.ru/content/File/43198335569.pdf
    • https://tucsonhomewindowtint.com/wp-content/plugins/super-forms/uploads/php/files/f883d1b738b07460a894254e222b5683/5910175508.pdf
    • http://4998horo.gmmwireless.com/contents/files/7253450730.pdf
    • http://sofia-es.tokyo/yamituki-n/uploads/files/42836078433.pdf
    • http://boekenwinkelindex.nl/images/uploads/podek.pdf
    • http://circuitoinsulargc.com/documentos/file/51469925640.pdf
    • http://alacarte-husum.de/userfiles/file/bowuwekupovibebuxijupite.pdf
    • https://hgindustrial.eu/userfiles/files/finiguwupesesutabani.pdf
    • http://secoinblock.com/upload/files/14232297245.pdf
    • http://www.hcibatiment.fr/wp-content/plugins/formcraft/file-upload/server/content/files/161358990ed480---96806204170.pdf
    • http://jagatjyotischool.org/jagatjyotischool/userfiles/file/rurowom.pdf
    • https://centrorevisionimonregalese.it/file/refemuf.pdf
    • http://maketmaster.ru/admin/ckfinder/userfiles/files/36556410536.pdf
    • https://creativesilhouettes.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16149a341d80c3---58742205913.pdf
    • https://kolkataangikar.org/ckfinder/userfiles/files/46400383042.pdf
    • http://bluecars.pl/userfiles/file/tatiz.pdf
    • https://premiersuli.hu/files/files/punivazaxotazekitadumej.pdf
    • http://bonaparte-kerkrade.nl/fckeditor/ckfinder/userfiles/file/7294163461.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b2c0.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xB2C0 16792 bytes
font_01_sfnt_off0000cad7.bin
3889bbb79421eb4aafcfc22c0efa1f58b51e434049d4738e44a8d4463131f24b
pdf-font-stream PDF embedded font (sfnt) at offset 0xCAD7 10676 bytes
font_02_sfnt_off0000e333.bin
3ff9d09fddda9f60b00506eecff725ac614434257ede94f06ef00bd5c2e28fc8
pdf-font-stream PDF embedded font (sfnt) at offset 0xE333 17872 bytes