Malicious PDF — malware analysis report

Static analysis result for SHA-256 9fb942673f28bc82…

MALICIOUS

PDF

67.8 KB Created: 2020-11-11 18:02:36 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-05
MD5: 53f6f58eeda8439bccc54cefcb601bc0 SHA-1: 1994819db0beb61da7b2d3c6cf70c95b9bc3d881 SHA-256: 9fb942673f28bc82c26037fe597bfca5e5cfb148897b8e8b638a63d5841a18a2
284 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF document contains a large number of external links, many pointing to disposable hosting, and one specifically uses a redirector to a URL containing 'baixar torch browser apk'. This, combined with the 'SE_BROWSER_INSTALL_LURE' heuristic, strongly suggests a social engineering attempt to trick the user into downloading and installing malicious software disguised as a browser update or extension. The ML classifier and ClamAV detection further support its malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • Browser extension / update installation lure high SE_BROWSER_INSTALL_LURE
    Document tells the user to install a browser extension, plugin, viewer, or browser update to view content — a common social-engineering path for credential theft and malware installation
  • 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.
  • 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://cctraff.ru/aws?utm_term=baixar+torch+browser+apk In PDF document text
    • https://cdn-cms.f-static.net/uploads/4375522/normal_5f8fe39443c0e.pdfIn PDF document text
    • https://fimetopim.weebly.com/uploads/1/3/4/3/134399480/5383645.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4374951/normal_5f8e6260d9f74.pdfIn PDF document text
    • https://wetuxabo.weebly.com/uploads/1/3/0/8/130873937/sekiperomapob-zisefazuma.pdfIn PDF document text
    • https://funebaxap.weebly.com/uploads/1/3/4/3/134399245/bidobaserujexixu.pdfIn PDF document text
    • https://fusefediwotedi.weebly.com/uploads/1/3/4/5/134589876/75a0cb7.pdfIn PDF document text
    • https://fupuvoriru.weebly.com/uploads/1/3/4/4/134494751/0889301.pdfIn PDF document text
    • https://bijasekimuku.weebly.com/uploads/1/3/4/5/134593614/viregepudaf.pdfIn PDF document text
    • https://jizonuwuko.weebly.com/uploads/1/3/0/8/130814311/vonugumazagusu.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/78646599-8276-431e-9048-513b368164aa/sabes_como_te_dicen_a_vos_nina.pdfIn PDF document text
    • https://s3.amazonaws.com/muwemivumazulax/gugeluxesabajatabos.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/de449d3d-6c7c-41a2-b38e-f6027410aa75/72325273375.pdfIn PDF document text
    • https://s3.amazonaws.com/gawabog/bls_provider_manual.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_off0000c7b4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC7B4 5404 bytes
SHA-256: 636c232b7eb92291d36a8d9d0051f8c885f42050df4bac4822330e5f865992c2
font_01_sfnt_off0000da23.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA23 11776 bytes
SHA-256: cad67ae17912d35851b4d53970d2c4bb14e5314f042f9a9b89588c5768fcd81f

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