Malicious PDF — malware analysis report

Static analysis result for SHA-256 73c8ae954317b525…

MALICIOUS

PDF

83.1 KB Created: 2021-09-18 07:29:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: b7661b3898ae3b0db796423f39bbae4b SHA-1: c8cdf7a2bde72748929525f3303670062fb8ae74 SHA-256: 73c8ae954317b525ae2d2eb807edc97abc80e39f297f911e8bbdd4ff805dca07
172 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF document containing embedded JavaScript, which is a common technique for executing malicious code. The PDF also hosts a link farm pointing to various external PDF files on compromised or disposable domains, suggesting an attempt to distribute further malicious content or phish users. The ML classifier and ClamAV detection strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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://birgatour.mn/js/ckfinder/userfiles/files/71142571951.pdf In PDF document text
    • https://jgranit.pl/userfiles/file/zamotigola.pdfIn PDF document text
    • http://philipwillettelaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/23134733788.pdfIn PDF document text
    • http://adas-muko.pl/photo/file/85976358410.pdfIn PDF document text
    • http://www.iamgoingto1996.com/wp-content/plugins/formcraft/file-upload/server/content/files/16132515043392---1178979675.pdfIn PDF document text
    • https://livresdarts.com/ckfinder/userfiles/files/dawuzijifizopopaxu.pdfIn PDF document text
    • https://nayyaralidada.net/alpha/ckfinder/userfiles/files/9250998791.pdfIn PDF document text
    • http://cyklo-sport-servis.cz/UserFiles/File/xesukebuxukuv.pdfIn PDF document text
    • http://www.zywawiara.pl/pliki/40586984593.pdfIn PDF document text
    • http://massimosusto.eu/userfiles/files/bodimiket.pdfIn PDF document text
    • http://xfswchem.com/upload/files/lafafapojafub.pdfIn PDF document text
    • https://datenglagi.com/contents/files/pebofo.pdfIn PDF document text
    • http://easternhoteljeju.com/FileData/ckfinder/files/20210918_C901837BC6654A00.pdfIn PDF document text
    • http://ambvetsanprospero.eu/userfiles/files/49846349415.pdfIn PDF document text
    • http://kingkady.com/uploadfile/files/24003417843.pdfIn PDF document text
    • https://www.officinadelgustoroma.com/wp-content/plugins/super-forms/uploads/php/files/4126867e03b7a84c864b61ba134f23d1/zupubapuzirerod.pdfIn PDF document text
    • http://centralgiving.com/media/userfiles/file/zajurekovup.pdfIn PDF document text
    • https://angkalaris.com/contents/files/nevigusovitu.pdfIn PDF document text
    • https://aquatrustfina.com/userfiles/file/90238043956.pdfIn PDF document text
    • http://saigondome.com/uploads/userfiles/file/vazojukapazekale.pdfIn PDF document text
    • https://www.elshandmadedesign.nl/ckfinder/userfiles/files/45482538288.pdfIn PDF document text
    • http://conhantaoankhanh.com/webroot/img/files/lodijij.pdfIn PDF document text
    • https://diversifiedhumansolutions.com/wp-content/plugins/super-forms/uploads/php/files/4bdd88c3f47c1e0507cab0c4b2a1eb0f/11392321876.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/ngfLrbzwjls/uplcv?utm_term=angry+birds+go+hack+unlimited+coins+and+gemsPDF 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_off0000d7b0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD7B0 20392 bytes
SHA-256: b623084327edf1e15ac0d059ecbb609cad1c145b2179098cd710b7e0696c8549
font_01_sfnt_off00010cc6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10CC6 11244 bytes
SHA-256: 19711136a84ab76f728d37c56212370896148094f47cfc5a96e1ef0b9afd1a56
font_02_sfnt_off000126d0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x126D0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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