Malicious PDF — malware analysis report

Static analysis result for SHA-256 31856bf70bbda47c…

MALICIOUS

PDF

87.8 KB Created: 2021-07-03 11:26:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 2986f5aa71e917a3ed8e0abd516bd85b SHA-1: 1b46298672e1316f642626576fc1028ce03ac4ad SHA-256: 31856bf70bbda47c8d095db8a40c735147a9539353cc4745310eb49339671a7c
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and a machine learning model also indicated maliciousness. The document contains a link farm pointing to compromised WordPress sites and other disposable hosting, suggesting an attempt to distribute malicious content or engage in phishing. While no scripts were explicitly extracted, the PDF structure and heuristics indicate it's designed to redirect users to potentially harmful URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

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 https://rhythmcprandfirstaid.com/wp-content/plugins/super-forms/uploads/php/files/c20e08b12047131dc31c0958c57410ae/fakevit.pdf In PDF document text
    • https://aliencosmicexpo.com/wp-content/plugins/formcraft/file-upload/server/content/files/160749236e595c---73316614272.pdfIn PDF document text
    • http://arabic.cz/ckfinder/userfiles/files/17657901792.pdfIn PDF document text
    • http://lovesushiscv.com/uploads/files/24824685374.pdfIn PDF document text
    • http://kokalietudarbnica.lv/files/files/nebusogelibupiro.pdfIn PDF document text
    • http://www.grupohk.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160926dae8ac10---mifupijetuxebitakoxalas.pdfIn PDF document text
    • https://belgradenightlife.info/wp-content/plugins/super-forms/uploads/php/files/l1te9ssmn6fqi8mdg0apc6g72d/82799072153.pdfIn PDF document text
    • http://gallery4walls.com/upload/editer/file/6402251431.pdfIn PDF document text
    • https://web-sila.ru/wp-content/plugins/super-forms/uploads/php/files/5df868e63be85471144bc086c9d64366/2965002483.pdfIn PDF document text
    • https://anukulagrotech.com/userfiles/file/gizojid.pdfIn PDF document text
    • http://escolacaritas.com/wp-content/plugins/formcraft/file-upload/server/content/files/16086dc49e8ca1---33561810689.pdfIn PDF document text
    • https://ketgate.eu/wp-content/plugins/super-forms/uploads/php/files/f7fbb352e47ed25004e03928a76adfb0/23417181001.pdfIn PDF document text
    • http://bradhelferlaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/dadupidugexali.pdfIn PDF document text
    • http://haiphongcontest.com/images/files/kogodeperupetuziwagexarun.pdfIn PDF document text
    • https://electrabicycles.pl/app/webroot/uploads/file/16201816128583.pdfIn PDF document text
    • http://www.acefence.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609fbd870c3db---derajarunugapox.pdfIn PDF document text
    • https://alternativecarrepair.com/userfiles/file/80500419734.pdfIn PDF document text
    • http://www.caribbeandentist.com/wp-content/plugins/formcraft/file-upload/server/content/files/16087c6fcea3f8---gitotujenirijafujo.pdfIn PDF document text
    • https://nikosdimos.gr/userfiles/file/98375033284.pdfIn PDF document text
    • http://nd-58.ru/wp-content/plugins/super-forms/uploads/php/files/f4336b5b2cc326b7bd0213be26a94cc5/zaxikenaresaxorezosa.pdfIn PDF document text
    • https://loskutova.site/wp-content/plugins/super-forms/uploads/php/files/1c9daf4faeaf6db523f32227b2ecc31b/72358475189.pdfIn PDF document text
    • http://studiogaleazzo.eu/userfiles/files/79631514525.pdfIn PDF document text
    • http://greenbrier101.com/userimages/nikaribamofelojur.pdfIn PDF document text
    • http://www.naturapreserved.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607cbcdda0b23---sotorigobivirip.pdfIn PDF document text
    • http://www.asslar.de/downloads/danirobinakawasopovipafi.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/zMnd8XtcwSM/uplcv?utm_term=ethoxylated+mono+and+diglyceridesPDF 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_off0000f0e5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0E5 18172 bytes
SHA-256: 81543f8629a48a076096415d41dcd45f53e18c622d13b31f5677ee48863b70fe
font_01_sfnt_off0001208b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1208B 11016 bytes
SHA-256: 744f7b2ae5fed618a93f53b45cf7be19af401d132a47dccc206c73f4a6fe34da
font_02_sfnt_off000139c5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x139C5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1