Malicious PDF — malware analysis report

Static analysis result for SHA-256 41ef7af15e3a6539…

MALICIOUS

PDF

80.3 KB Created: 2021-10-04 22:58:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-20
MD5: 8f7cb777a5f49ba6ec1724c1a34b3c6a SHA-1: 73f3f1bf9c04a3a8946696161836bc4efe689083 SHA-256: 41ef7af15e3a6539c9e13fbcc6db0910fd33392c470f5d5aa10f2f72c796ac3f
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF was flagged by ML and ClamAV as malicious, with heuristics indicating it functions as a link farm. The document body is heavily obfuscated, but the presence of numerous embedded URLs, many pointing to disposable domains, strongly suggests a phishing or malware distribution attempt. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic specifically calls out the link farm nature and use of disposable hosting.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

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://polesprogettazioni.com/userfiles/files/35252813637.pdf In PDF document text
    • https://rivieresoceanie.com/ckfinder/userfiles/files/25515566010.pdfIn PDF document text
    • https://fnb-concepts.com/images/uploads/files/sugozipivovem.pdfIn PDF document text
    • http://hejia-ele.net/upload/39264528079.pdfIn PDF document text
    • http://www.hgbehringer.de/img/files/files/22716040693.pdfIn PDF document text
    • http://ville-dammarie.com/ckfinder/userfiles/files/63568880591.pdfIn PDF document text
    • http://www.armstrongre.com/files/files/kuroboguvilif.pdfIn PDF document text
    • http://unitekinfostructures.com/userfiles/file/9307690217.pdfIn PDF document text
    • http://thermcom.cz/userfiles/file/52189243957.pdfIn PDF document text
    • https://www.rath-catering.de/wp-content/plugins/formcraft/file-upload/server/content/files/161460706abf33---57423492048.pdfIn PDF document text
    • https://birsamundapark.in/userfiles/files/ramarix.pdfIn PDF document text
    • https://keralatemples.info/ckfinder/userfiles/files/20149465784.pdfIn PDF document text
    • http://dmhu.eu/uploads/uplib/file/xigalu.pdfIn PDF document text
    • http://gevenschoenen.nl/ckfinder/userfiles/files/diwivusit.pdfIn PDF document text
    • http://zhuxintrading.com/uploads/ckfinder/files/20210927/16326819957595.pdfIn PDF document text
    • http://ristorantebiscione.com/userfiles/files/56822878926.pdfIn PDF document text
    • http://opusincertum.it/userfiles/files/lamomejopilef.pdfIn PDF document text
    • http://boxerdapolenta.com/cmsimple/images/file/55770445337.pdfIn PDF document text
    • http://symbolfoods.com/files/file///wewifizokanun.pdfIn PDF document text
    • http://lindseyderence.com/userfiles/files/33070886358.pdfIn PDF document text
    • http://skolky.info/foto/images/file/vomibufuga.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/PmAiG5ZyT-k/uplcv?utm_term=orthocentre+of+acute+trianglePDF 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_off0000d127.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD127 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e939.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE939 19380 bytes
SHA-256: 55be89071365e30233e7e4a83bc7f76fc9d3c19a6caa1ec350f4e1bc44f11db0
font_02_sfnt_off00011bdf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11BDF 10572 bytes
SHA-256: 19fbf24bc8d051feecbb7a91440e066a2c5eaf612711d3d776a30afb8c13f9da

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