Malicious PDF — malware analysis report

Static analysis result for SHA-256 81f16a37855336a0…

MALICIOUS

PDF

79.0 KB Created: 2021-09-20 16:51:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 1b656878caeb255b28dacca5f3f2a398 SHA-1: 366a9ee0228900c26e2ce262e095ac54a81b1096 SHA-256: 81f16a37855336a0ca5145e5e595446d5d854daf0f97251438440eb7267c2c57
154 Risk Score

Malware Insights

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

This PDF document was flagged by multiple heuristics, including a critical ClamAV detection and an ML classifier, indicating malicious intent. The 'SE_CALLBACK_LURE' heuristic strongly suggests the document is designed to trick the user into calling a fraudulent phone number, consistent with tech support scams or billing fraud. Embedded JavaScript was also detected, which could be used to further exploit the user or download additional payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

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
  • 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.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://fnb-concepts.com/images/uploads/files/walewikapas.pdf In PDF document text
    • http://parkwestresidences.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613780893c751---siluzadamiz.pdfIn PDF document text
    • https://avis-medical.ma/wp-content/plugins/super-forms/uploads/php/files/1a6049f6c475ff6c5ba37e2f34bf501c/87128489185.pdfIn PDF document text
    • http://thanglong.vn-greenenergy.com/ckfinder/userfiles/files/22469833316.pdfIn PDF document text
    • http://zhongyuemedia.com/filespath/files/20210920053242.pdfIn PDF document text
    • http://rotarybrescello.it/userfiles/files/57383375742.pdfIn PDF document text
    • http://polenes.cl/userfiles/file/9758564524.pdfIn PDF document text
    • http://thomasgearon.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/sagaduzokanawexu.pdfIn PDF document text
    • http://libertyquad72.fr/userfiles/file/vekatewizinadozaludidiwas.pdfIn PDF document text
    • http://holidayservicemarsala.it/userfiles/files/wedutikugatojuvij.pdfIn PDF document text
    • http://carshopm.com/js/upload/files/zinufajitovepa.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/S30rS-6n6vg/uplcv?utm_term=ak+notepad+apkPDF 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_off0000c9fb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC9FB 10052 bytes
SHA-256: 2e773056336698fc6bad38913db4aeb9b9f32262ddc97c9895b9f675f2484feb
font_01_sfnt_off0000e07a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE07A 20976 bytes
SHA-256: 759504c7fd3e8f00a4036a3347a619a62831bb65c830a5e5a19422e42e6758fe
font_02_sfnt_off00011796.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11796 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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