Malicious PDF — malware analysis report

Static analysis result for SHA-256 9a40cea2a2b451bc…

MALICIOUS

PDF

77.6 KB Created: 2021-09-18 04:52:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: e8e06227a3d3ea77616d463d96293c09 SHA-1: 75928d0af31a58fca32d22661ae38317af347266 SHA-256: 9a40cea2a2b451bc98180226337e60f043d3277e5ef12e8073f6b4742518ce31
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, indicating a high likelihood of malicious intent. It contains numerous embedded URLs, many of which point to compromised CMS upload directories or disposable hosting, suggesting it's part of a link farm designed to redirect users to malicious sites. The presence of PDF-specific heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' further supports this. While no scripts were explicitly extracted, the nature of the URLs and the overall structure suggest it could be used to deliver a second-stage payload or facilitate phishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://52fotki.ru/ckfinder/userfiles/files/20319141528.pdf In PDF document text
    • http://alburigiott.it/userfiles/files/tegakezoronutavuzenewo.pdfIn PDF document text
    • http://kriosispl.com/cote_dor_import/admin/ckfinder/userfiles/files/pamotesujobit.pdfIn PDF document text
    • http://sakra.sk/storage/file/40748108044.pdfIn PDF document text
    • https://webgirls-studio.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613c7a7c0578c---wujezetinafow.pdfIn PDF document text
    • http://thoitranglani.com/upload/files/mujagebi.pdfIn PDF document text
    • http://gaineyranchaz.com/userimages/66918492316.pdfIn PDF document text
    • http://www.gradur.ba/wp-content/plugins/formcraft/file-upload/server/content/files/1614372995985a---59203599432.pdfIn PDF document text
    • http://dinhvi5s.com/images/newtech/files/vefazi.pdfIn PDF document text
    • http://efcosmetic.com/uploadfile/files/1374615875.pdfIn PDF document text
    • http://xycrusher.com/d/files/26806578237.pdfIn PDF document text
    • https://yingzhaoliuart.com/upload/file/tupopasoz.pdfIn PDF document text
    • http://zjqzzx.com/uploadfile/file/2021090607523773499.pdfIn PDF document text
    • http://beastyenergy.com/userfiles/file/kaxosoz.pdfIn PDF document text
    • http://sineadstone.com/userfiles/file/39755943260.pdfIn PDF document text
    • http://masterkontroll.hu/ckfinder/userfiles/files/wumamuponatajajem.pdfIn PDF document text
    • https://alexspa.pl/userfiles/file/85240671374.pdfIn PDF document text
    • http://eyela.kr/uploadfile/fckeditor/file/31557318566.pdfIn PDF document text
    • https://shinyjewellers.com/wp-content/plugins/super-forms/uploads/php/files/sg52us2glhdq77e89dc4iua9ir/selagugukudep.pdfIn PDF document text
    • https://wineart.online/userfiles/file/21986058755.pdfIn PDF document text
    • http://bsp-oblspl.org/ckfinder/userfiles/files/87290538128.pdfIn PDF document text
    • http://salamino.pl/userfiles/file/40406395424.pdfIn PDF document text
    • http://xn--80aafbladvtgxneccoge3bt.xn--p1ai/pict/file/16190515115.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=demon+slayer+episodes+season+1PDF link annotation
    • 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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ca55.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCA55 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e26c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE26C 10624 bytes
SHA-256: c804cb9fa6cfb2442dc241e35302cba7748ed8316d16fd21e848129b90d06bc7
font_02_sfnt_off0000fab0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFAB0 18000 bytes
SHA-256: e6378bf7a130e8ee2815702896e5b059cc653a1a5abe86cda2aa054371f7d957

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