Malicious PDF — malware analysis report

Static analysis result for SHA-256 26538128816c49f7…

MALICIOUS

PDF

80.5 KB Created: 2021-10-09 16:42:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 9fae55ec9854e1d9b5b0d2d2748dbe8d SHA-1: 431a660fd24cf391571969ae2ecf9146dc315385 SHA-256: 26538128816c49f70e6c29b16ada7bcfba3a8aab04cfbb9d3cfcdebefd3f29fc
184 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and multiple external URIs, some of which point to compromised WordPress sites. The 'SE_CALLBACK_LURE' heuristic indicates the document is designed to prompt the user to call a phone number, a common tactic in callback phishing and tech support scams. The ML classifier and ClamAV detection strongly suggest malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 8

  • 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 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.
  • 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 http://senvietsystem.com/ckeditor/upload/files/karuli.pdf In PDF document text
    • http://xn--aknmedical-yub.com/uploads/file/78547735466.pdfIn PDF document text
    • http://conkheror.com/ckfinder/userfiles/files/lavetafiwuvaxevuzevipuxib.pdfIn PDF document text
    • http://acevina.com/webroot/img/files/42757410799.pdfIn PDF document text
    • http://crediramasrl.it/public/file/luwuzewulov.pdfIn PDF document text
    • https://showerdrainplus.com/uploads/files/202110021517271685.pdfIn PDF document text
    • http://fine-trading-knotwork.com/uploads/media/94795040088.pdfIn PDF document text
    • https://rlmahtani.com/userfiles/files/sarobeletedovibobuzafete.pdfIn PDF document text
    • https://southafricapools.com/contents/files/88825167516.pdfIn PDF document text
    • https://howardsteeves.com/wp-content/plugins/super-forms/uploads/php/files/15ad37b31eb0a778b27e36d8218d863f/vabinubolini.pdfIn PDF document text
    • http://minhledtran.com/luutru/files/turumotanutawuxomexamed.pdfIn PDF document text
    • http://billsky.ee/files/file/26696722742.pdfIn PDF document text
    • http://bamor.org/userfiles/file/vezomakagesodu.pdfIn PDF document text
    • https://possamaiferramenta.it/uploads/file/figevulugipopu.pdfIn PDF document text
    • http://www.stratcareerservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/1615a91fc10cfd---54972100506.pdfIn PDF document text
    • https://al-farh-iq.com/upload/userfiles/file/demugonejuzevabikokizip.pdfIn PDF document text
    • https://tanvietnamdinh.com/uploads/files/18652899869.pdfIn PDF document text
    • http://hoangminhsaigon.vn/@dmin/js/ckfinder/userfiles/files/91482588007.pdfIn PDF document text
    • https://caribemed.com/userfiles/file/4480427987.pdfIn PDF document text
    • http://huucodatlanh.com/userfiles/file/gikuka.pdfIn PDF document text
    • https://kueapem.com/contents/files/zidubutudij.pdfIn PDF document text
    • http://chistogood.ru/admin/ckfinder/userfiles/files/79622234693.pdfIn PDF document text
    • http://topopentertainment.com/wp-content/plugins/formcraft/file-upload/server/content/files/161515f84b3886---2691851787.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1KS0DP0cxss/uplcv?utm_term=standard+shipping+tracking+numberPDF 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_off0000d724.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD724 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ef36.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF36 16700 bytes
SHA-256: 619b44370303c360107b7a3196c051d030a5d8a7a02d55ba8f7d9c45a0f13c47
font_02_sfnt_off00011a98.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11A98 11200 bytes
SHA-256: 6d8f8fc8e24bf4acc1251051c922aad4c0a747c70912a1ef122ed8730b9cd997

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