Malicious PDF — malware analysis report

Static analysis result for SHA-256 bc8532bd3b2d311f…

MALICIOUS

PDF

69.8 KB Created: 2021-04-17 04:18:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: 2a6815674c63f0aa978cde7bf630b430 SHA-1: 28258eeccaa07bb571bea7f3e03393d5a5112d6a SHA-256: bc8532bd3b2d311f92b7f7ff0991fbc5cbee5e04b035399cce3bd4acaea05128
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, specifically as a phishing trojan. The document body is heavily obfuscated, but the presence of numerous external URLs, many hosted on seemingly legitimate domains but pointing to suspicious PDF files, suggests a phishing or malware distribution attempt. The 'PDF_SEO_DISPOSABLE_LINK_FARM' heuristic indicates a tactic to obscure the true destination of links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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/93854264345.pdf In PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/wajuso.pdfIn PDF document text
    • https://www.jts.org.jo/sites/default/files/webform/wijuwimitixatedus.pdfIn PDF document text
    • http://www.grotekeukens.be/sites/default/files/webform/gmawards2018/98751459569.pdfIn PDF document text
    • https://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/13471650610.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/1289321409.pdfIn PDF document text
    • https://www.woonsocketri.org/system/temporary/webform/kebadewanizokodijixupid.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/46846662681.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/1eyvgo/aqOO/~3/6naE_Nh8_CY/uplcv?utm_term=casio+g+shock+gd+100+manual+pdfPDF link annotation
    • https://thesanfordschool.asu.edu/sites/default/files/webform/83703622856.pdfIn PDF document text
    • https://minorsoncampus.princeton.edu/system/files/webform/xadumiwedom.pdfIn PDF document text
    • https://ec.europa.eu/eip/agriculture/sites/default/files/webform/sukazejaso.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_off0000d3a1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD3A1 5636 bytes
SHA-256: b4f6d9a38ccf7c70bad81e52ff3ca35a4b6962fbd465fab78d65ca8872e93f01
font_01_sfnt_off0000e6ad.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6AD 10524 bytes
SHA-256: 8c63822bb26db18710380d1c5a629ff23ecac947f3ad735df903592e7347d119