Malicious PDF — malware analysis report

Static analysis result for SHA-256 b961cfc81f44a56b…

MALICIOUS

PDF

92.3 KB Created: 2021-09-07 14:54:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: d792c4d03911763e2095562887ff45f8 SHA-1: 1f5b4103265a87ff04846194db4d8a9a9de10332 SHA-256: b961cfc81f44a56b9ad1b5e6da288bfb22a67c3d5ba9c49e5718340090ac82e3
156 Risk Score

Malware Insights

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

The sample is identified as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous external links, many pointing to compromised CMS upload storage or disposable hosting, suggesting a link farm used for phishing or malware distribution. The PDF structure and link farm behavior are consistent with spearphishing attachments designed to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://elearning-chemistry.ro/userfiles/file/nomaduzikexideximafux.pdf In PDF document text
    • https://www.willmarshelter.com/ckfinder/userfiles/files/kivajoxikulowafowido.pdfIn PDF document text
    • http://anhuishangbiao.com/upload_fck/file/2021-5-8/20210508083301965686.pdfIn PDF document text
    • https://psychotherapie-dr-albrecht.de/wp-content/plugins/formcraft/file-upload/server/content/files/1606cf2b40232a---fusebapagazis.pdfIn PDF document text
    • https://www.urban-quartz.co.uk/wp-content/plugins/super-forms/uploads/php/files/2b2bc113a73d07a3005a46b001f4a703/lorakifapofopet.pdfIn PDF document text
    • https://web-sila.ru/wp-content/plugins/super-forms/uploads/php/files/4c5237ead8ce86cdbcb9525ac5dc53b4/bokewilawanibibejako.pdfIn PDF document text
    • http://turystyka.powiatlubartowski.pl/admin/ckfinder/userfiles/files/11236570535.pdfIn PDF document text
    • http://austral-immo.com/userfiles/files/gabubezug.pdfIn PDF document text
    • http://suacuacuonthanhhoa.com/upload/files/38290875817.pdfIn PDF document text
    • http://soles2walk.cz/data/file/26661046779.pdfIn PDF document text
    • http://primaria-ciocirlia.ro/media/file/72022645688.pdfIn PDF document text
    • https://indobaliart.com/sitefiles/file/94600100639.pdfIn PDF document text
    • http://localhomesales.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1606d2137b7af3---61407535274.pdfIn PDF document text
    • https://www.darrellstuckey.com/wp-content/plugins/formcraft/file-upload/server/content/files/16095fdc51c423---wapelimavetowuki.pdfIn PDF document text
    • https://communeouchamps.fr/userfiles/file/17756341270.pdfIn PDF document text
    • https://kawanmto.info/contents/files/gakeluzovilozabitu.pdfIn PDF document text
    • http://sobsai.com/ckfinder/userfiles/files/segumuwegovogikidum.pdfIn PDF document text
    • http://www.bash.cl/media/file/3811198117.pdfIn PDF document text
    • http://www.cargeacrew.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160ba700a76841---zoteje.pdfIn PDF document text
    • http://www.xpresswedding.com/wp-content/plugins/formcraft/file-upload/server/content/files/161143b17978bd---votofuvakomopoxitewukes.pdfIn PDF document text
    • http://hauptlawoffice.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/96755022689.pdfIn PDF document text
    • http://bizwd.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ecc1603dcfe---4688108826.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/fzgW7-mxBc0/uplcv?utm_term=python+pil+pdf+to+pngPDF 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_off00010506.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10506 18424 bytes
SHA-256: 1be95ace08b580ce282ce8a4e2dbff93d5f7ebb5591dac4f503e8d3e228819f0
font_01_sfnt_off00013533.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13533 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00014d4a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14D4A 10332 bytes
SHA-256: b4edab133aaca2ebc1522f85a3436035013a5cddaac6bc0346a6a7e9781e9d6a

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