Malicious PDF — malware analysis report

Static analysis result for SHA-256 f86790a915031892…

MALICIOUS

PDF

66.9 KB Created: 2021-04-18 21:46:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: e2b55016a1a2c77bbe3ea6acc4223010 SHA-1: 4d6601cb52188a55cf9c5ef70ef0dc3a91f1573c SHA-256: f86790a91503189228fb552bd3ec405da28cea9b27a775d79050df854d826ebb
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript T1203 Exploitation for Client Execution

The PDF file was flagged by ML classifiers and ClamAV as malicious, indicating a phishing attempt. The document body, though heavily obfuscated, suggests a lure related to 'Intel audio driver for windows 7 ultimate 32 bit', aiming to trick users into downloading a payload. The presence of numerous embedded URLs, many pointing to disposable or unknown domains, further supports the link farm tactic used to distribute the malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 https://ambrose.edu/sites/default/files/webform/sudelo.pdf In PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/56601188302.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/80982398497.pdfIn PDF document text
    • http://www.friendlycc.com/sites/default/files/webform/topevonizudurazot.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/54125375098.pdfIn PDF document text
    • https://www.jts.org.jo/sites/default/files/webform/76938035167.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/DOqCt-cVA4I/uplcv?utm_term=intel+audio+driver+for+windows+7+ultimate+32+bitPDF link annotation
    • https://lib.asu.edu/system/files/webform/nexeginexepor.pdfIn PDF document text
    • https://www.healthdata.org/sites/default/files/resumes/68382108709.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/febapaxugodikuzakepob.pdfIn PDF document text
    • https://ec.europa.eu/eip/agriculture/sites/default/files/webform/vifixofixif.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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c69b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC69B 5656 bytes
SHA-256: 10d9f22a065821bc19771055de0dcb837399e3bb14f507bbdf8fd58b81193a7c
font_01_sfnt_off0000d9e8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9E8 10844 bytes
SHA-256: 5e45d61092b20575b0859724244fc9835957536eec035bab38b71724cfd4d6ef

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