Malicious PDF — malware analysis report

Static analysis result for SHA-256 c35c75d404daeedd…

MALICIOUS

PDF

74.4 KB Created: 2021-09-16 14:45:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: f831b0d5f726842c3b9db60b5fc29ba1 SHA-1: 54eac2a051313d0419887e87eab7105aed91badb SHA-256: c35c75d404daeeddcbe94ee5ef3843073814fb38bf3e4ceb11db57799b04c307
216 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1553.005 Security Software Tampering

The PDF was flagged by ML classifiers and ClamAV as malicious, exhibiting characteristics of a phishing or scam document. It contains a link farm pointing to compromised CMS uploads and disposable hosting, suggesting an attempt to distribute malicious content. The heuristic 'SE_SECURITY_BYPASS' indicates the document likely instructs the user to disable security software, a common tactic in malware delivery. While no scripts were explicitly extracted, the PDF structure and embedded URLs suggest it's designed to trick users into downloading further malicious payloads or engaging with a callback scam.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

Heuristics 8

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Security software disable instruction high SE_SECURITY_BYPASS
    Document instructs the user to disable antivirus or security software — unusual for ordinary documents and high-risk in an unsolicited file
  • 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://netwindowvn.com/uploads/userfiles/file/99369488744.pdf In PDF document text
    • http://tatagz.com/uploadfile/files/jegavukajezogijami.pdfIn PDF document text
    • https://vibangnhadat.com/uploads/files/fesimegejetovum.pdfIn PDF document text
    • https://boyanbolyarski.com/userfiles/file/duguweradidepurilenerozex.pdfIn PDF document text
    • http://xingzhongjing.com/userfiles/file/20210915202838_1109438379.pdfIn PDF document text
    • https://humantouchtranslations.com/wp-content/plugins/formcraft/file-upload/server/content/files/1/16138da367a80f---futezufux.pdfIn PDF document text
    • http://3asoft.vn/img/files/sodel.pdfIn PDF document text
    • https://ipssecurityconsultants.com/ckfinder/userfiles/files/zelatolomuper.pdfIn PDF document text
    • http://2017.letnifestiwal.pl/ckfinder/userfiles/files/kijusepanosojukavobizifi.pdfIn PDF document text
    • http://kimsanghun.com/upload/userfiles/file/2021982250492437.pdfIn PDF document text
    • http://ort168.com/upload/ckeditor/files/nelufaxatezig.pdfIn PDF document text
    • https://kaptenhoki.info/contents/files/kukuvowok.pdfIn PDF document text
    • http://pebyte.com/wp-content/plugins/super-forms/uploads/php/files/nu0qma32su1161cvpqs84um11b/mumivebu.pdfIn PDF document text
    • https://iamtimeshare.com/userfiles/file/6244478357.pdfIn PDF document text
    • https://royal-art.pl/uploads/userfiles/files/1728549974.pdfIn PDF document text
    • http://jngf.cn/files/file/21835878559.pdfIn PDF document text
    • http://tehnicgaz.eu/files/file/26989038065.pdfIn PDF document text
    • http://aviteksural.ru/admin/ckfinder/userfiles/files/60099233556.pdfIn PDF document text
    • http://sinching.com/uploadpic/files/202109010809052286.pdfIn PDF document text
    • http://cerrutistudio.eu/userfiles/files/13376929440.pdfIn PDF document text
    • http://hoaiduc.edu.vn/ckfinder/userfiles/files/46618995354.pdfIn PDF document text
    • https://pecsikult.hu/files/file/138615234.pdfIn PDF document text
    • http://ziepniekkalns.lv/wp-content/plugins/formcraft/file-upload/server/content/files/1613f2db473564---87918162474.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/PmAiG5ZyT-k/uplcv?utm_term=aa+mirror+android+auto+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_off0000c1dc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC1DC 16836 bytes
SHA-256: f0852c9696260545d19f5513b8a7eb8d77484f05bf957933cc99f464e408b3cd
font_01_sfnt_off0000ecd3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xECD3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000104ea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x104EA 10380 bytes
SHA-256: 55629fe22062a990aa5252227f7eb1c207db7d4bd0aa5145556bb48967463a26

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