Malicious PDF — malware analysis report

Static analysis result for SHA-256 91b28a3b10a642ac…

MALICIOUS

PDF

78.9 KB Created: 2021-09-14 11:47:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 15c682cd16fa6b1f21dc128ce10688e4 SHA-1: c89dfdc2e4fb8783a5215904a8f86fe28bfe1b9c SHA-256: 91b28a3b10a642acc09a25d7df8ffd071a874ce46072787134911cec58a4aef1
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is a PDF containing a link farm designed to redirect users to various PDF files hosted on potentially compromised websites. The presence of a 'harmony os 2.0 download apk' lure in one of the URLs suggests a phishing or social engineering attempt to trick users into downloading the malicious PDF. The ML classifier and ClamAV detection strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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.
  • Urgency / deadline lure low SE_URGENCY_LURE
    Document contains urgency or deadline language ('account will be terminated', 'action required within 24 hours', etc.) — useful context, but low-signal without other findings
  • 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://huuphongplastic.vn/uploads/images/files/44732652872.pdf In PDF document text
    • https://larrialdiak.es/files/galeria/files/57160571095.pdfIn PDF document text
    • https://jungleflightchiangmai.com/Uploads/files/dibobodumuriguzi.pdfIn PDF document text
    • http://nextgenship.net/upload/file/20210903163064609619.pdfIn PDF document text
    • https://www.asoriofrio.org/ckfinder/userfiles/files/dalolim.pdfIn PDF document text
    • http://www.neslihanonur.com/wp-content/plugins/super-forms/uploads/php/files/69c180728ae08761c59e14da45e70dd8/zuribezuwe.pdfIn PDF document text
    • https://phase1acoustics.com/wp-content/plugins/formcraft/file-upload/server/content/files/161355a4aedf21---duwop.pdfIn PDF document text
    • http://4seasonstours.in/userfiles/file/9453530215.pdfIn PDF document text
    • http://aldobini.it/userfiles/files/96820879946.pdfIn PDF document text
    • http://kleinschadenexpert.de/userfiles/file/57923998176.pdfIn PDF document text
    • http://unityproductions.com/upload/files/guwiwuleros.pdfIn PDF document text
    • https://zippy-inc.com/app/webroot/userfiles/files/24753459236.pdfIn PDF document text
    • http://autovoda.ru/upload/files/77139387144.pdfIn PDF document text
    • https://nwdglobal.com/ckfinder/userfiles/files/depana.pdfIn PDF document text
    • http://www.dereformasenalicante.com/archivos/files/jafovusawizozapug.pdfIn PDF document text
    • http://saigonradio.com/userfiles/file/91711896058.pdfIn PDF document text
    • https://backcountryplayground.com/wp-content/plugins/super-forms/uploads/php/files/420bfe74349d5927163075ce4a7cea14/63720652796.pdfIn PDF document text
    • http://limeitec.com/upfiles/editor/files/13861695501.pdfIn PDF document text
    • http://kamerton.nl/clientfiles/xobujovefuwaga.pdfIn PDF document text
    • http://zhongjiukeji.com/upload_fck/file/2021-9-3/20210903121830801464.pdfIn PDF document text
    • http://zafirkort.com/uploads/files/98042930817.pdfIn PDF document text
    • http://prepearl.com/uploadsfile/30939134599.pdfIn PDF document text
    • http://fjzy18.com/image/uload/files/susotanese.pdfIn PDF document text
    • http://wolfpackbasketballacademy.com/content_docs/fopumigotiporuzegedomek.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=harmony+os+2.0+download+apkPDF 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_off0000cb9e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB9E 10824 bytes
SHA-256: 8a331987048082923fdaf1519aaeb00dad8bb5fce63862864f9dae10ed180c85
font_01_sfnt_off0000e4a1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4A1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000fcb3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFCB3 19064 bytes
SHA-256: 7cfce51940b854cb2481d5a82d24678a125053d87de36c0870e14a4eaf08b952

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