Malicious PDF — malware analysis report

Static analysis result for SHA-256 85f8716947f94fbb…

MALICIOUS

PDF

67.2 KB Created: 2021-04-18 02:11:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-31
MD5: c045e1e6d42e09c45048262768a53b88 SHA-1: d536478aab88020bb78c5fd0745ca8c12c8288af SHA-256: 85f8716947f94fbbaaddc716cb62ef7f9bc0af578f5468eabc7e6056ed57db3b
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 document contains numerous embedded URLs, many of which point to disposable or unknown hosting, suggesting a link farm or phishing lure. The presence of PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, indicating the document is designed to host many links on potentially untrusted domains. Although no scripts were explicitly extracted, the PDF structure and heuristics suggest it is designed to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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 http://cicatsalud.com/html/sites/default/files/webform/foxegedukob.pdf In PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/gafazibo.pdfIn PDF document text
    • https://www.mothercare.ro/sites/default/files/webform/resumes/susumijifiwef.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/44437875789.pdfIn PDF document text
    • https://www.woonsocketri.org/system/temporary/webform/bogobovimefegaf.pdfIn PDF document text
    • http://russian-ice-spb.ru/sites/default/files/webform/files/loxigexaxezirizedud.pdfIn PDF document text
    • http://www.pbttphtk.gov.my/sites/default/files/webform/238550972.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/15194676649.pdfIn PDF document text
    • https://www.jts.org.jo/sites/default/files/webform/nisegat.pdfIn PDF document text
    • https://vectorcorp.net/sites/default/files/webform/resume/dutaberapowuniz.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/S30rS-6n6vg/uplcv?utm_term=how+much+is+a+2011+chevy+traverse+worthPDF link annotation
    • https://thesanfordschool.asu.edu/sites/default/files/webform/lezedatabamivija.pdfIn PDF document text
    • https://lib.asu.edu/system/files/webform/bidemuf.pdfIn PDF document text
    • https://minorsoncampus.princeton.edu/system/files/webform/tuvoluxasivawujunaz.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_off0000ca30.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCA30 5548 bytes
SHA-256: 9509a404d6514fcb69e904a523c91546d56dcf3d3360ab15559bff94bee28365
font_01_sfnt_off0000dd05.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD05 10428 bytes
SHA-256: c691e20297a09f9d5c6a189900437c592071d901926db29a2bae6702c43833c4