Malicious PDF — malware analysis report

Static analysis result for SHA-256 b934fbbe1a729e41…

MALICIOUS

PDF

66.4 KB Created: 2021-04-20 15:45:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-07
MD5: 86e2d97e17e75077e595dc992d0274ce SHA-1: c033d5f38605acaff3fcb81513150e9962aba1bb SHA-256: b934fbbe1a729e414153fbd0b815191f2c15987b2575064f8aaa18395f8da4f0
126 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous distinct hosts and embedded URLs, suggesting an attempt to direct users to malicious sites. The presence of external URIs and the 'PDF_SEO_DISPOSABLE_LINK_FARM' heuristic strongly support this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/13178745316.pdf In PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/15194676649.pdfIn PDF document text
    • https://www.dgs-interparts.be/sites/default/files/60165950635.pdfIn PDF document text
    • https://www.enwidth.com/sites/default/files/webform/resumes/ziwisotug.pdfIn PDF document text
    • https://www.jwico.com/sites/default/files/webform/23528315583.pdfIn PDF document text
    • http://www.friendlycc.com/sites/default/files/webform/tojatovovezugunubi.pdfIn PDF document text
    • https://www.pharoxglobal.com/sites/default/files/webform/7322176875.pdfIn PDF document text
    • http://www.friendlycc.com/sites/default/files/webform/16921441106.pdfIn PDF document text
    • https://www.enwidth.com/sites/default/files/webform/resumes/90018929780.pdfIn PDF document text
    • https://www.ofalloncasting.com/sites/default/files/webform/tirudekamevajoluzagobumi.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/vojowavujelosapol.pdfIn PDF document text
    • https://www.jsif.org/sites/default/files/webform/rijuluzevowogadabiwi.pdfIn PDF document text
    • https://www.a1touchsolution.nl/sites/default/files/95216779236.pdfIn PDF document text
    • https://www.woonsocketri.org/system/temporary/webform/54194604641.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/~3/3vuEKuznOb8/uplcv?utm_term=who+makes+dometic+rv+air+conditionersPDF link annotation
    • https://campusrec.princeton.edu/system/files/webform/34970544405.pdfIn PDF document text
    • https://lib.asu.edu/system/files/webform/98562832035.pdfIn PDF document text
    • https://www.healthdata.org/sites/default/files/resumes/18848190838.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_off0000c8fb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC8FB 5284 bytes
SHA-256: 03cabe06fe97c5f32b27f4a238a5b0fb446eec525b2d8891600d6ab0b611fd1c
font_01_sfnt_off0000dad2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDAD2 9896 bytes
SHA-256: 9a6b93e3180cf68644228c2519f93a7452e418c0ecff0b009847950df039976f

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