Malicious PDF — malware analysis report

Static analysis result for SHA-256 91a8f756dcfb32c4…

MALICIOUS

PDF

72.9 KB Created: 2021-09-28 13:42:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 96a6401c1b85cb849b8c6c391f65ce9f SHA-1: e165fbdca3fd24f7118e46baf73f4ca938a85eb7 SHA-256: 91a8f756dcfb32c43673d99870e9cbd4282957827e912bb8bfeeccb5aa381380
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The file is identified as malicious by ML classifiers and ClamAV, with multiple heuristics indicating it's a link farm pointing to compromised websites. The PDF contains numerous embedded URLs, suggesting an attempt to redirect users to malicious domains for phishing or further exploitation. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics strongly suggests a malicious intent to leverage compromised infrastructure for distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://synerhu.ru/uplcv?utm_term=defining+and+non+defining+relative+clauses+exercises+pdf+with+answers PDF link annotation
    • http://vucert.vn/uploads/files/botokemipivug.pdfIn PDF document text
    • http://absolutelyneon.com/userfiles/file/23095513076.pdfIn PDF document text
    • http://bigyikesmedia.com/home/xtremweb/public_html/consultinstitute/web/upload/files/99459850902.pdfIn PDF document text
    • http://kowalstwwo.pl/public/cms/images/file/42857278933.pdfIn PDF document text
    • https://proektasis.gr/admin/spaw2/uploads/files/polilebexorinaluvinafu.pdfIn PDF document text
    • https://exihomes.com/userfiles/files/68530431581.pdfIn PDF document text
    • http://traiteurluc.com/userfiles/file/59325333635.pdfIn PDF document text
    • http://youngthisyear.com/ckfinder/userfiles/files/lelabi.pdfIn PDF document text
    • http://autosoftware.company/autoresponders_images/files/57656486917.pdfIn PDF document text
    • http://kapsalonindex.nl/images/uploads/18750991267.pdfIn PDF document text
    • https://cowichanmusicfestival.com/userfiles/file/43457516449.pdfIn PDF document text
    • https://vsetinrally.cz/userfiles/file/figol.pdfIn PDF document text
    • http://www.atccs3.it/atccs3/fckeditor/editor/ckfinder/userfiles/files/52906037799.pdfIn PDF document text
    • http://ac-kenigsberg.ru/files/file/36891262908.pdfIn PDF document text
    • http://boek.se/bilder_umeny/File/nefawubezileteka.pdfIn PDF document text
    • https://journeypeople.cc/wp-content/plugins/super-forms/uploads/php/files/1896501953c5b9d1a58227c914701e8b/40091065605.pdfIn PDF document text
    • http://shlawllc.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/bemobomaxexalapuvilaguso.pdfIn PDF document text
    • http://cuacuongiare.vn/upload/files/pijuwudisalunebavalezuk.pdfIn PDF document text
    • http://xn--80aagkbrca3apkgkee0a1bi.xn--p1ai/ckfinder/userfiles/files/6831571387.pdfIn PDF document text
    • http://www.larucheapain.fr/ljk/file/majodenos.pdfIn PDF document text
    • https://history.tlshaa.org.tw/ckfinder/userfiles/files/xezemixoj.pdfIn PDF document text
    • http://nattuvaartha.com/assets/ckfinder/core/connector/php/uploads/files/50084256730.pdfIn PDF document text
    • https://www.diktu.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614d42270da5e---15731188095.pdfIn PDF document text
    • http://www.theflightfest.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613d39d4b20aa---35308105915.pdfIn PDF document text
    • http://fluitec.fr/ressource/site-image/files/kutamugawupixuvenifijabe.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_off0000b69d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB69D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ceb4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCEB4 11256 bytes
SHA-256: 47d4957648dd25c85406b4bf11194119f0833cface4666c58ba659ca63189165
font_02_sfnt_off0000e8f0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE8F0 17164 bytes
SHA-256: e4656818b87d38362679310fd3524bbb04b652925f0d544416e094552224385c