Malicious PDF — malware analysis report

Static analysis result for SHA-256 29bf1c3d539ba88a…

MALICIOUS

PDF

77.8 KB Created: 2021-04-16 20:53:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-06-30
MD5: f16d6ca10aa6a15418b439a61fd0c4ac SHA-1: 9465f1aef5cf22c2b2d9535edd82e451076f3850 SHA-256: 29bf1c3d539ba88a2e550711359fbf509971899afc9952b01f38ab364e050078
126 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, indicating a high likelihood of malicious intent. The document body, though heavily obfuscated, contains references to 'Acer aspire tc-895 power supply upgrade', suggesting a lure for phishing or scam purposes. The presence of numerous embedded URLs, many pointing to seemingly legitimate domains but potentially serving as part of a link farm or redirection scheme, further supports this assessment. No scripts were extracted, but the PDF structure itself is indicative of malicious activity.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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 http://portal-mysigma.com/system/files/student-proof/72808970040.pdf In PDF document text
    • https://www.dgs-interparts.be/sites/default/files/57515461030.pdfIn PDF document text
    • http://www.friendlycc.com/sites/default/files/webform/29579557159.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/35757612566.pdfIn PDF document text
    • https://www.termis.org/system/files/webform/98565071062.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/~3/1KS0DP0cxss/uplcv?utm_term=acer+aspire+tc-895+power+supply+upgradePDF link annotation
    • https://www.healthdata.org/sites/default/files/resumes/53082175038.pdfIn PDF document text
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/50075528518.pdfIn PDF document text
    • https://drones.princeton.edu/system/files/webform/zifogisabivaloxigisosobu.pdfIn PDF document text
    • https://lib.asu.edu/system/files/webform/vabomabexajamoja.pdfIn PDF document text
    • https://ec.europa.eu/eip/agriculture/sites/default/files/webform/72323592377.pdfIn PDF document text
    • https://minorsoncampus.princeton.edu/system/files/webform/posilo.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_off0000efb0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFB0 5932 bytes
SHA-256: f8776d090083e8e4c991b13ccf518809859e95da0463e2747cfd604274e7a455
font_01_sfnt_off00010409.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10409 11212 bytes
SHA-256: 7c8f4107195ea12bd9719b65edf73b17912c8bc5a5df02a164f949c26568d2f0

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