Malicious PDF — malware analysis report

Static analysis result for SHA-256 b850ef7e8471ffd1…

MALICIOUS

PDF

72.9 KB Created: 2021-04-12 01:58:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-01
MD5: ef53f8e93dcd1f5c4a7e5c32b1f01b83 SHA-1: 43c81b9d0562faa73931a7caf35449f4f6fa785c SHA-256: b850ef7e8471ffd1f5f45870f5ea7b834ea11e879892a2152d1cac7828dd50bc
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

This PDF document was flagged as malicious by ClamAV and an ML classifier. The file embeds a large number of external links characteristic of an SEO link farm. Specific URLs and indicators for this sample are listed in the indicators section.

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://www.osgeurope.com/sites/osg-corporate.dev/files/webform/fifomibap.pdf In PDF document text
    • https://www.ofalloncasting.com/sites/default/files/webform/tasuwagorefovufozibojer.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/ginigiwosumomigari.pdfIn PDF document text
    • http://www.pbttphtk.gov.my/sites/default/files/webform/1232685222.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/wajuso.pdfIn PDF document text
    • https://www.blplegal.com/sites/default/files/webform/25596831819.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/jowodudarazobipadumalo.pdfIn PDF document text
    • http://seiary.com/sites/default/files/webform/rec/kutovaduro.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/YTWXjIUwRh0/uplcv?utm_term=cities+skylines+post+officePDF link annotation
    • https://www.vub.be/sites/vub/files/webform/lijulur.pdfIn PDF document text
    • https://community.princeton.edu/system/files/webform/13590028771.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/34970544405.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/jelozubunumi.pdfIn PDF document text
    • https://community.princeton.edu/system/files/webform/xakefabobadu.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_off0000e1b0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE1B0 4776 bytes
SHA-256: fe11adc4d6c520294f59cdd3e4a4067f787ac73ee34f7182eaa059c1cb13d19f
font_01_sfnt_off0000f218.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF218 10720 bytes
SHA-256: aad25e3d8222d75b006779158ffd4e3539cc45af2f85d00dc6f53e09b2b0d6e4

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