Malicious PDF — malware analysis report

Static analysis result for SHA-256 9d6c4d31d94e8488…

MALICIOUS

PDF

84.4 KB Created: 2021-09-21 01:54:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: dde4eea72ccfc1d91ae2877e2684e92d SHA-1: b2055ae8890b33682fac337c8b7385b594785ee9 SHA-256: 9d6c4d31d94e8488661d76b3d01288f60232ec4e34557d66b3572d045a1361cc
172 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which point to files hosted on compromised WordPress sites or other disposable domains, forming a link farm. The presence of embedded JavaScript and a high ML classifier score, combined with ClamAV detection as 'Pdf.Phishing.Trojan', strongly suggests a malicious intent to trick users into downloading further malicious content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, indicating it's not meant for direct user consumption but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9860

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.
  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://vietnamairlinescorp.org/js/ckfinder/userfiles/files/rokalotitebuvutaxi.pdf In PDF document text
    • https://learningsolution.ca/userfiles/files/85079741345.pdfIn PDF document text
    • https://service-panev.com/userfiles/mipabuke.pdfIn PDF document text
    • http://gzcil.com/uploadfile/files/kagumiso.pdfIn PDF document text
    • http://comicpapyrus.com/wp-content/plugins/super-forms/uploads/php/files/85202656745ed8cb68b6a2c42f88be5c/ralolojizegujogoru.pdfIn PDF document text
    • https://hamayeshniroo.com/shop/file/15588311057.pdfIn PDF document text
    • https://clubesolbra.com/uploads/files/89421858682.pdfIn PDF document text
    • https://biharlokmanch.org/userfiles/file/nufupegarusi.pdfIn PDF document text
    • http://noithatmfc.com/media/ftp/file/85133316342.pdfIn PDF document text
    • https://computerzone.pk/file/76757708323.pdfIn PDF document text
    • http://sattosushi.com/uploads/files/nodowunag.pdfIn PDF document text
    • https://haps.company/wp-content/plugins/super-forms/uploads/php/files/97ff38651d8436a63363b17162f6f15e/sutoduxubufagawesenabimi.pdfIn PDF document text
    • http://manvilastrust-org.bvirani.com/ckfinder/userfiles/files/55594722555.pdfIn PDF document text
    • http://redondoclassicburger.com/uploads/files/soliterelofisomapunavede.pdfIn PDF document text
    • http://toyotarent.kr/FileData/ckfinder/files/20210917_CCBADC44FBCB8D27.pdfIn PDF document text
    • https://clove7.com/userfiles/file/bozetugekufuni.pdfIn PDF document text
    • https://manhalhealing.com/userfiles/file/likakugukugizimeromaboxev.pdfIn PDF document text
    • http://twapp.freshkon.com/upload/files/39383177595.pdfIn PDF document text
    • https://accidentmatters.com/ckfinder/userfiles/files/gibejat.pdfIn PDF document text
    • http://woykoff.hu/upload/file/56323357322.pdfIn PDF document text
    • http://henanshuangxin.com/d/files/powidasefinef.pdfIn PDF document text
    • http://nc2e.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1612fa73d67916---dilojuwum.pdfIn PDF document text
    • http://konferencii.org/js/ckfinder/userfiles/files/lupafeveduxejudefafavis.pdfIn PDF document text
    • http://www.lbtfilm.com/uploads/files/fuvugil.pdfIn PDF document text
    • http://ohmytour.kr/FileData/ckfinder/files/20210908_661F4E7D750F252C.pdfIn PDF document text
    • https://suacuachuyennghiep.com/uploads/files/41980017351.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/zMnd8XtcwSM/uplcv?utm_term=pptx+convertir+a+pdfPDF 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_off0000e139.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE139 19516 bytes
SHA-256: 854d5821ccce687d620397049c4adbe51db223e9d9ccf493ab111c444bb93810
font_01_sfnt_off00011418.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11418 10568 bytes
SHA-256: c934fd0b089ec700c856ce8632a4870a6765a2c4764416fc55993023a892c3dc
font_02_sfnt_off00012c61.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12C61 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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