Malicious PDF — malware analysis report

Static analysis result for SHA-256 afffd7317d2db5e2…

MALICIOUS

PDF

74.2 KB Created: 2021-09-26 05:24:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: b807021726e35d9242769600dc45fca6 SHA-1: 4172fa356a4ec451295c6f2a24bbce4bcc33cf01 SHA-256: afffd7317d2db5e28e7c979d6c2204e3ae4b43431ce18c32d7293266e2f874f9
96 Risk Score

Malware Insights

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

The PDF contains a large number of embedded URLs, many of which point to external PDF files hosted on various domains. Several heuristics indicate this is a link farm, with some links pointing to compromised CMS upload storage. The ML classifier strongly flagged this PDF as malicious, suggesting it's part of a malicious distribution or SEO poisoning campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

Heuristics 5

  • 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://rowerowaszkola.pl/imgturysta/files/99082121144.pdf In PDF document text
    • http://chinhlytailieuluutru.com/media/ftp/file/69730226021.pdfIn PDF document text
    • https://argumentua.com/i/file/xowox.pdfIn PDF document text
    • http://seednseed.com/admin/fckfiles/file/gurubolopi.pdfIn PDF document text
    • https://termofriz.rs/files/84047286566.pdfIn PDF document text
    • https://kimtuong.vn/isc/public/files/fckupload/file/41222638877.pdfIn PDF document text
    • https://360clothing.indicsys.com/home/www360cl/public_html/uploads/images/files/rirupagipuguzixuwupod.pdfIn PDF document text
    • https://spyboarcams.com/files/16074381524.pdfIn PDF document text
    • http://wiskind.com/filespath/files/20210920161820.pdfIn PDF document text
    • http://balbu.eu/uploads/news/file/5912401621.pdfIn PDF document text
    • http://seoulgreeter.com/userData/board/file/lirawera.pdfIn PDF document text
    • https://nutstudio.it/userfiles/file/95803295359.pdfIn PDF document text
    • https://unosms.us/userfiles/file/saloserevekejiwofuwubidew.pdfIn PDF document text
    • http://hiro-seiko.com/upload/files/9879108520.pdfIn PDF document text
    • https://landlorddebtadvisory.com/wp-content/plugins/super-forms/uploads/php/files/357a8765466acd4d133ff7cf660cce03/97341144185.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614cfaa8c0816---sobefemesepef.pdfIn PDF document text
    • http://zetrade.cz/userfiles/file/zolowamarowemuxovu.pdfIn PDF document text
    • https://elemonbg.com/Files/File/43793904866.pdfIn PDF document text
    • https://www.baust.edu.bd/app/webroot/ckfinder/userfiles/files/gemiwive.pdfIn PDF document text
    • http://biogenetec.tw/image/files/20210926_022604.pdfIn PDF document text
    • http://landonintergroup.com/ckfinder/userfiles/files/67383530125.pdfIn PDF document text
    • http://neodev.space/wp-content/plugins/formcraft/file-upload/server/content/files/161425df0d88e5---kavedonowamirodefu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/6naE_Nh8_CY/uplcv?utm_term=free+web+series+app+for+iosPDF 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_off0000badb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBADB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d2f2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD2F2 10304 bytes
SHA-256: 40be13a57c97b3689952e98d0cfe070d988c8cecd602afbdd16eea9f5bac0070
font_02_sfnt_off0000ea21.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA21 19028 bytes
SHA-256: 518d36eba43ea9f7ce60222c4135a0dd616bdc60409eb2461e4ea4d4c8d2b10f