Malicious PDF — malware analysis report

Static analysis result for SHA-256 d871e0ddf3e66409…

MALICIOUS

PDF

73.1 KB Created: 2021-04-20 17:51:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: a2c1ac8e37af873b3413b8b894771eb2 SHA-1: 149f21e2bf80ba07056dab0c5a4aee30663bd3ef SHA-256: d871e0ddf3e6640941f86ce50af6c719c66be766ec996ac8af554acfab756a1e
126 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to domains that appear to be part of a link farm, suggesting a phishing or malware distribution scheme. The ML classifier and ClamAV detection strongly indicate malicious intent, specifically identified as Pdf.Phishing.Trojan. The document body, though heavily obfuscated, suggests a lure related to calculus, likely to trick users into clicking the malicious links. No scripts were extracted, but the overall structure and heuristic firings point to a phishing attack.

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 https://www.uts.cw/sites/default/files/webform/58994315224.pdf In PDF document text
    • https://www.jwico.com/sites/default/files/webform/71926652616.pdfIn PDF document text
    • https://www.clinicasfantamaria.ro/sites/default/files/webform/33767122539.pdfIn PDF document text
    • https://natsihwa.org.au/sites/default/files/webform/mufuwujaxerafesa.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/28695523124.pdfIn PDF document text
    • https://www.uts.cw/sites/default/files/webform/89737617204.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/99544266771.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/99284441703.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/dalobasowi.pdfIn PDF document text
    • https://www.ofalloncasting.com/sites/default/files/webform/34904816646.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/Uplcv/~3/3vuEKuznOb8/uplcv?utm_term=how+to+find+speed+in+calculusPDF link annotation
    • https://gradfutures.princeton.edu/system/files/webform/42179508969.pdfIn PDF document text
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/10713621665.pdfIn PDF document text
    • https://lib.asu.edu/system/files/webform/90369837207.pdfIn PDF document text
    • https://ec.europa.eu/eip/agriculture/sites/default/files/webform/27560642257.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_off0000e207.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE207 5108 bytes
SHA-256: f37d52628e7fec5e8a5f7aaf8cdcb2eff49cb2a7abcecba24c84274ab7e4eea9
font_01_sfnt_off0000f393.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF393 10868 bytes
SHA-256: 28637c0db30d831e2f00fa3130407374d18731469daf5cc6f426243bb9f87e3e

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