Malicious PDF — malware analysis report

Static analysis result for SHA-256 bb665a116451dbae…

MALICIOUS

PDF

71.1 KB Created: 2021-04-26 23:29:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: 3f316ec9fd6cfb3418b0568eb9afd0b4 SHA-1: 2f1ad6ade9637ebf12fed802e5d83139e955de10 SHA-256: bb665a116451dbae281f7c249f35484ba4103e72cd2aab54cd9b61ac6baef985
126 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous embedded URLs pointing to potentially malicious sites. While no scripts were explicitly extracted, the PDF structure and the nature of the heuristics suggest an attempt to redirect the user to malicious content, likely for phishing or malware distribution.

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 http://cicatsalud.com/html/sites/default/files/webform/17654710786.pdf In PDF document text
    • https://ambrose.edu/sites/default/files/webform/74647609277.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/56601188302.pdfIn PDF document text
    • http://portal-mysigma.com/system/files/student-proof/41429692510.pdfIn PDF document text
    • https://www.jwico.com/sites/default/files/webform/23528315583.pdfIn PDF document text
    • https://www.visitsavannah.com/sites/default/files/webform/mubojezelu.pdfIn PDF document text
    • https://www.jwico.com/sites/default/files/webform/47965191786.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/setafemamuf.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/~3/1xuhb7AK25c/uplcv?utm_term=schwinn+exercise+bike+170+manualPDF link annotation
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/46273532178.pdfIn PDF document text
    • https://www.healthdata.org/sites/default/files/resumes/fanonexujezurexuli.pdfIn PDF document text
    • https://drones.princeton.edu/system/files/webform/voretazejujuwewoz.pdfIn PDF document text
    • https://printandmail.princeton.edu/system/files/webform/fasulegok.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_off0000d8c7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD8C7 5780 bytes
SHA-256: 0dbbb9222f82b7733322f9c5f58dd106300928ce8fb7a9f57673f21e7747e598
font_01_sfnt_off0000ec6d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC6D 10512 bytes
SHA-256: 530730e0c9b24fa7690d20bdc2d8865ddc8d4c1904ac741cc75f3c0f696d3e30