Malicious PDF — malware analysis report

Static analysis result for SHA-256 f4b8e376b15e5a5d…

MALICIOUS

PDF

81.6 KB Created: 2021-04-08 23:19:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-06-04
MD5: 2a7ffb48db91a58adf7cf4d7afebf3ef SHA-1: 9a4f2aa97fca86328dedf2981284d5c9f56f22e7 SHA-256: f4b8e376b15e5a5d946c15543f6272a3532577403542375229e7e68c4c601e7e
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 heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' suggests the document is designed to host numerous links, likely for phishing or distributing further malware. While no scripts were explicitly extracted, the presence of embedded URLs and the nature of the heuristics point towards an attack pattern involving redirection to potentially harmful external sites.

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://ambrose.edu/sites/default/files/webform/kubuxodadiwozubak.pdf In PDF document text
    • https://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/xetomaroronep.pdfIn PDF document text
    • https://www.uts.cw/sites/default/files/webform/bofuwidesuxugebogaxa.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/bidepe.pdfIn PDF document text
    • https://aboss.by/sites/default/files/webform/12404161593.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/xexazud.pdfIn PDF document text
    • http://www.pbttphtk.gov.my/sites/default/files/webform/73261430544.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/71027525942.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/DOqCt-cVA4I/uplcv?utm_term=mathematical+symbols+table+pdfPDF link annotation
    • https://thesanfordschool.asu.edu/sites/default/files/webform/fapivo.pdfIn PDF document text
    • https://drones.princeton.edu/system/files/webform/61493424170.pdfIn PDF document text
    • https://printandmail.princeton.edu/system/files/webform/21338807989.pdfIn PDF document text
    • https://minorsoncampus.princeton.edu/system/files/webform/27732669772.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://scripts.sil.org/OFLIn PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000df19.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF19 5544 bytes
SHA-256: a31e9eeb5253469a3ff86e0d605e25301ea3b80f2cdbcc3090fcd81390de14a0
font_01_sfnt_off0000f1db.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF1DB 1800 bytes
SHA-256: daad3f347a4f42f432ee9983e619a7c063e36761dba5934b469418034847e28e
font_02_sfnt_off0000fa69.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA69 13380 bytes
SHA-256: 281097db76afb6b6d3e552c045aebf24259bb5702d5a42019bbfb932290601a4
font_03_sfnt_off0001278d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1278D 16656 bytes
SHA-256: b5e2803624b0975020f3a53532666b4cffbbba5ec07e1a87768b96532d4349fe

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