Malicious PDF — malware analysis report

Static analysis result for SHA-256 dfd9b312bbfb5bf6…

MALICIOUS

PDF

71.1 KB Created: 2021-09-22 16:38:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 3bdb980171f1d742b8fcadc14e8a5a10 SHA-1: 177579a21c6210555244e0505e0c062479c3fe88 SHA-256: dfd9b312bbfb5bf6d2f1a2576bff280c351e841f46f24587707d6f3e64394f17
126 Risk Score

Malware Insights

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

The PDF contains a large number of embedded URLs pointing to external PDF files, indicating it functions as a link farm. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' specifically flags this behavior, suggesting a phishing or malware distribution scheme. The ML classifier and ClamAV detection strongly support the malicious nature of this file.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://wastran.ru/uplcv?utm_term=why+do+my+apps+keep+closing+android PDF link annotation
    • http://pibar.tw/uploads/files/202109171752092509.pdfIn PDF document text
    • https://semangkabiji.com/contents/files/foridenebidosivuwumujuso.pdfIn PDF document text
    • http://cyuanmei.com/userfiles/file/wonizetulenifobitunuwira.pdfIn PDF document text
    • https://currenwatch.myhost360.cn/file/upload/files/09-06-23-53-18-26.pdfIn PDF document text
    • https://opsclown.it/ckfinder/userfiles/files/74401101450.pdfIn PDF document text
    • http://alfavit.tv/userfiles/file/99215667423.pdfIn PDF document text
    • https://suma.ca/upload/editor/file/17600965480.pdfIn PDF document text
    • https://bearings.vn/images/ckeditor/files/mituvudobomaguw.pdfIn PDF document text
    • http://kirks-pool.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612fc39a47d1a---kitelomutexirute.pdfIn PDF document text
    • http://www.sec-ollivier-associes.fr/www/upload/file/39629324811.pdfIn PDF document text
    • https://pharmnet.cz/ckfiles/files/files/12649191891.pdfIn PDF document text
    • https://motiwalainstitutes.org/userfiles/file/4888781165.pdfIn PDF document text
    • http://socukorglutamatmentesfuszer.hu/ckfinder/userfiles/files/lemaxavubivasu.pdfIn PDF document text
    • http://packamate.com/userfiles/27792158641.pdfIn PDF document text
    • https://schachverein-marchhoefe.ch/fcsr/news/upload/file/85565463452.pdfIn PDF document text
    • http://energyexcess.com/userfiles/file/suwopa.pdfIn PDF document text
    • http://plafondchauffant.fr/img/user/file/40968071156.pdfIn PDF document text
    • http://odpadykj.cz/UserFiles/File/fivanoteminumikegujeso.pdfIn PDF document text
    • https://leise.ru/admin/ckfinder/userfiles/files/gumizovemekuzufojewad.pdfIn PDF document text
    • http://harryreichert.de/uploaded_pics/News/file/tilajafowitoseb.pdfIn PDF document text
    • http://daglichtfilters.nl/ckfinder/userfiles/files/59494856752.pdfIn PDF document text
    • https://postelezmasivu-olomouc.cz/ckfinder/userfiles/files/tikilabigodotulepob.pdfIn PDF document text
    • http://eros-arena.name/eros/userfiles/file/69929390962.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_off0000b361.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB361 16608 bytes
SHA-256: acc53a9a8e9f12c078fa35a953e7347b35646159cd2e60ae308914f6ed239d09
font_01_sfnt_off0000dd99.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD99 11060 bytes
SHA-256: 859ba654d8f78f52d5bb6ed01bdb702086c22022054e9b7727f7069093fa9f42
font_02_sfnt_off0000f6ee.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6EE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1