Malicious PDF — malware analysis report

Static analysis result for SHA-256 a637d8a44bf4e5cd…

MALICIOUS

PDF

85.4 KB Created: 2021-06-13 03:03:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-16
MD5: a21f01e1836a9e608ea244725257b8e4 SHA-1: d81f3a1c0d11c16df2c3cb074f48e29f37ee639f SHA-256: a637d8a44bf4e5cda5cebd100c7e53f13ab0b7307f49563391763f782f9494df
176 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

This PDF file is identified as malicious by multiple heuristics and a machine learning classifier. It contains numerous embedded URLs that point to compromised WordPress sites and other disposable hosting, suggesting a link farm designed to redirect users to malicious content. The heuristic 'SE_CALLBACK_LURE' indicates it may also be used for callback phishing or tech-support scams.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 7

  • 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.
  • 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.
  • 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://cructi.ru/uplcv?utm_term=what+is+network+unlocked+phone PDF link annotation
    • https://freedomtampons.com/wp-content/plugins/super-forms/uploads/php/files/b29edfd29ff5f3abedae46e5de3a1b90/nigemokaserujamelabugidak.pdfIn PDF document text
    • https://irantruck.ir/data/file/63365553116.pdfIn PDF document text
    • http://www.julitolaschools.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b06f9b6489e---17772588212.pdfIn PDF document text
    • https://atlanthealth.com/wp-content/plugins/super-forms/uploads/php/files/8763c9992ebecde62707d0940eb5b8c5/88855538146.pdfIn PDF document text
    • https://nhaban24h.com.vn/wp-content/plugins/super-forms/uploads/php/files/1r0l1b9a6db4oavsape02jsiut/73410985224.pdfIn PDF document text
    • https://www.karenlovelee.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607f45df80c8e---digonaludabiteboxibe.pdfIn PDF document text
    • https://webmodeli.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b31d2b1b0d3---93018533653.pdfIn PDF document text
    • http://lifemartrealestateconnect.com/wp-content/plugins/super-forms/uploads/php/files/86qbh5aqlvk58cjnha2cch4k13/vulaxufadubokajo.pdfIn PDF document text
    • https://teenvolunteerhouston.org/wp-content/plugins/super-forms/uploads/php/files/d827d8917f7cb97220876f3ac75cc340/kanemiwexatifuboret.pdfIn PDF document text
    • https://egokituz.eus/files/galeria/files/58076281799.pdfIn PDF document text
    • https://www.tai.gr/wp-content/plugins/formcraft/file-upload/server/content/files/160b7c4c1dbde4---18936001184.pdfIn PDF document text
    • https://www.okcfarmersmarket.com/wp-content/plugins/super-forms/uploads/php/files/0124fe0ca9e6773223a3b705819fac1a/86078452077.pdfIn PDF document text
    • https://sidexsideaudio.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606c7a020c763---wudosifevugegigovozi.pdfIn PDF document text
    • https://phase1acoustics.com/wp-content/plugins/formcraft/file-upload/server/content/files/16072c8db1d22a---wujatexuzinek.pdfIn PDF document text
    • https://betonwerkendejonge.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160a3f8f546a22---24649772617.pdfIn PDF document text
    • https://enville.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608c288030cff---gakojavimosiz.pdfIn PDF document text
    • http://interiorconsignments.com/media/file/30924041652.pdfIn PDF document text
    • http://vytvarnyobchod.cz/UserFiles/File/lotonizatamapoxozifewelad.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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_off000110a4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x110A4 5332 bytes
SHA-256: 7f9d2ea9e07998718f286ca646c48fba3af6e8549a84c76b53ab597b339d7ddf
font_01_sfnt_off000122d5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x122D5 11132 bytes
SHA-256: ec3e96010a482cd9590867fca9998defb59b329664fb1c1bf0f473b14d9a0fb5