Malicious PDF — malware analysis report

Static analysis result for SHA-256 d31b95886064fbb6…

MALICIOUS

PDF

83.6 KB Created: 2021-09-19 21:06:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 28244fe01b289c76e146edfd875d7a0c SHA-1: fdefbdd2365f228a4e84ad40608de0e9fe8fa611 SHA-256: d31b95886064fbb645ba63edbb251318d8b175358e09a9a4f93b9b99d3167f6a
126 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, with heuristics indicating it functions as a link farm. It contains numerous embedded URLs pointing to other PDF files, suggesting a campaign to distribute malicious content or manipulate search engine results. The primary attack pattern involves luring users to a network of linked PDFs, likely as a form of phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

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 http://palmdale.thepokeluau.com/uploads/files/xuzomozukodubawivejozis.pdf In PDF document text
    • http://chi-kara.net/userfiles/file/10590269100.pdfIn PDF document text
    • http://caerulumpharma.com/upload/files/75617915038.pdfIn PDF document text
    • https://www.oalysa.cz/ckfinder/userfiles/files/debitur.pdfIn PDF document text
    • https://dakhoathienhoa.net/images/files/zuvopujupum.pdfIn PDF document text
    • https://medarbindia.org/ckfinder/userfiles/files/98701816912.pdfIn PDF document text
    • https://elnativocoffee.com/silver/upload/files/zafamawidenazifobikesu.pdfIn PDF document text
    • http://localhomesales.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/161371b11203d6---dalerilobowukugagirizo.pdfIn PDF document text
    • http://getsolarnj.com/userfiles/file/52708687738.pdfIn PDF document text
    • https://qpshouse.com/upload/image/file/tarilimofugon.pdfIn PDF document text
    • http://kuehllawpc.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/jifosimosatixe.pdfIn PDF document text
    • http://schoonhovensvrouwenkoor.nl/ckfinder/userfiles/files/wekovojawolabudedib.pdfIn PDF document text
    • https://srmhomes.com/images/bulk_images/files/67867059866.pdfIn PDF document text
    • https://harkakotony.hu/UserFiles/file/7389359962.pdfIn PDF document text
    • https://delcinfo.ru/img/files/files/fidosisu.pdfIn PDF document text
    • http://pillshop.ru/uimg/files/12683814752.pdfIn PDF document text
    • http://oiseau-bleu-morzine.com/userfiles/file/tekinubagipomud.pdfIn PDF document text
    • http://tlumacz-bialystok.pl/pliki/file/28396922653.pdfIn PDF document text
    • http://cdkuys.handysociality.com/upload/files/79562311412.pdfIn PDF document text
    • http://apothepharma.com/upload/files/dejegilinorejejam.pdfIn PDF document text
    • http://czyxchem.com/upload/files/83924151767.pdfIn PDF document text
    • http://exhibitionchannel.com/upload/35236434092.pdfIn PDF document text
    • http://www.akutrans.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613db9acacb46---vutusasotofirovixul.pdfIn PDF document text
    • http://teedinmaesai.com/user_img/file/15280786624.pdfIn PDF document text
    • http://3t-t.com/User_File/UpFile/file/20210905230644_amFkaXRvZGlsZWRlZmlzZXBvcmVqb2ppZA==.pdfIn PDF document text
    • http://prime-standard.com/piceditor/file/43246357719.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/cv9VXjIrmdE/uplcv?utm_term=acing+the+new+sat+mathPDF 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_off0000de35.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE35 10480 bytes
SHA-256: ee1828eae4b3b17928a5318180f9993c893d52881d0518b4d1d60ee8cbeaa1e5
font_01_sfnt_off0000f5ed.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5ED 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010dff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10DFF 19184 bytes
SHA-256: b30c633d3b9cec3405228dd2839a1c8714f1ff62092b606ec401936b68a33640