Malicious PDF — malware analysis report

Static analysis result for SHA-256 441084fef65c40ec…

MALICIOUS

PDF

84.2 KB Created: 2021-09-10 10:44:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: f5ea6045bf13adb082f4b5b96e4ca1c1 SHA-1: 7441a746008661ee5c765a6954534c67f7b18af3 SHA-256: 441084fef65c40ecd932804648f7ec4b7089757aad65ce23b7139220cfd1e925
96 Risk Score

Malware Insights

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

The PDF contains a link farm, with multiple URLs pointing to other PDF files hosted on various domains. Several heuristics indicate this is a link farm on disposable or compromised hosting, suggesting a malicious intent to manipulate search engine results or distribute further payloads. The ML classifier strongly flagged this PDF as malicious, supporting the assessment of a malicious attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://ozt.zielonetarasy-cieplice.pl/uploads/userfiles/files/37438925926.pdf In PDF document text
    • http://narnivet.com/userfiles/files/xawowapiwatelebikemurowok.pdfIn PDF document text
    • http://noavarservice.com/ckfinder/userfiles/files/38120183075.pdfIn PDF document text
    • http://tincorner.vn/uploads/files/xutadekosofikowomuj.pdfIn PDF document text
    • https://mjrspot.com/fckimages/file/denurevatomovagidokubi.pdfIn PDF document text
    • http://termocity.by/pics/files/nonasopabiz.pdfIn PDF document text
    • http://newworldss.com/uploads/file/lodirutositapi.pdfIn PDF document text
    • http://www.veronicaneal.com/wp-content/plugins/formcraft/file-upload/server/content/files/1/1613221e8d2aa4---53044367391.pdfIn PDF document text
    • https://yar-net.ru/userfiles/file/92176983865.pdfIn PDF document text
    • https://greenboo.vn/uploads/files/zapebodiwuwebotulemepo.pdfIn PDF document text
    • http://www.nbrownies.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161346ce095956---rajofuwenulijobuda.pdfIn PDF document text
    • https://www.rapn.ru/ckfinder/userfiles/files/xelux.pdfIn PDF document text
    • http://orvositudasbazis.eu/images/upload/file/bututor.pdfIn PDF document text
    • http://vidiniaibreketai.lt/userfiles/file/75917032593.pdfIn PDF document text
    • http://ajisushionline.com/uploads/files/mitozukopanubafufatoj.pdfIn PDF document text
    • http://aquarium-kochi.com/app/webroot/ckfinder/userfiles/files/29353204755.pdfIn PDF document text
    • https://tahitotfalu.hu/ckfinder/userfiles/files/mopewufodid.pdfIn PDF document text
    • http://immobilieninvestors.com/userfiles/file/xemobiwobokowar.pdfIn PDF document text
    • http://myphammonly.com/luutru/files/lopadajodebimakowajiv.pdfIn PDF document text
    • http://www.uvhk.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613944e1755d4---14644084123.pdfIn PDF document text
    • http://gattoneva.pl/pages/userfiles/file/mapesadukefijozumaraz.pdfIn PDF document text
    • http://www.tecnotrefg.it/wp-content/plugins/formcraft/file-upload/server/content/files/161320a8b339ef---18222941645.pdfIn PDF document text
    • http://yuli-china.ru/d/files/28774439425.pdfIn PDF document text
    • http://hhoasis.org/app/webroot/img/fck/file/76446861492.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=movie+hd+apk+modPDF 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_off0000e5d9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE5D9 17740 bytes
SHA-256: 15e49d648d70a1c130ca06baecbc8d2535f4ca1332dc7d270b83dc44ff99377e
font_01_sfnt_off000113e4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x113E4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012bfb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12BFB 10292 bytes
SHA-256: 1213bf166a5d5869414ac23857e37655e9cee0a2a5ff31cf26048d615797f7ff