Malicious PDF — malware analysis report

Static analysis result for SHA-256 fc8d4b548e8702d9…

MALICIOUS

PDF

69.8 KB Created: 2021-04-15 07:34:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-05
MD5: b55d434dd998e029c6818a1ad933b122 SHA-1: 921161ea06dde349d2ba7597a41f49c4f0fe5c3a SHA-256: fc8d4b548e8702d913a16bb4e78db6a3208fa735d33c5e9a73d5a5138408f8ae
126 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The presence of external URIs and a link farm heuristic suggests the document is designed to redirect users to potentially harmful sites. Although no scripts were explicitly extracted, the PDF structure and embedded URLs point towards a phishing or malware distribution attempt, likely initiated via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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 https://www.a1touchsolution.nl/sites/default/files/87400145234.pdf In PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/55178968397.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/lavajaruzapelusudixavu.pdfIn PDF document text
    • https://www.dgs-interparts.be/sites/default/files/55949953827.pdfIn PDF document text
    • http://www.sumnercountyhospital.org/sites/default/files/webform/72664382884.pdfIn PDF document text
    • https://www.enwidth.com/sites/default/files/webform/resumes/fudigebifofonixetizitalu.pdfIn PDF document text
    • https://www.a1touchsolution.nl/sites/default/files/51131620028.pdfIn PDF document text
    • http://www.pbttphtk.gov.my/sites/default/files/webform/73261430544.pdfIn PDF document text
    • http://www.birdlifebotswana.org.bw/sites/default/files/webform/sightings-sketches/43600748611.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/80098342864.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/fenalop.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/~3/1xuhb7AK25c/uplcv?utm_term=math+worksheets+for+5th+grade+fractions+printablePDF link annotation
    • https://thesanfordschool.asu.edu/sites/default/files/webform/99818817157.pdfIn PDF document text
    • https://community.princeton.edu/system/files/webform/40347257249.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_off0000d23f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD23F 5844 bytes
SHA-256: b9a653191a085a08b8f5c0c337a47d7b2c35525d60018dc4f1d3b44b46bf6d44
font_01_sfnt_off0000e63c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE63C 10564 bytes
SHA-256: 0d8a1a047e4f33eed64ee459976e8417b131e9ad8fa835ec312819f866983003