Malicious PDF — malware analysis report

Static analysis result for SHA-256 20dd73f928b83f4a…

MALICIOUS

PDF

87.1 KB Created: 2021-09-02 08:56:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 9ada30252c081bec7d4b9cc778345079 SHA-1: e478116675b8564bd50d170b1f8204e203e995fd SHA-256: 20dd73f928b83f4a184ffb2c96ebfefa5439ebacfc7faad0775ea5ad8c0dfbe0
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file was identified as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. Heuristics reveal it functions as a link farm, with numerous URLs pointing to compromised CMS uploads and disposable hosting, suggesting it's used for distributing further malicious content or phishing. The document body is heavily obfuscated and unreadable, providing no direct user-facing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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 http://imagespa.mx/wp-content/plugins/formcraft/file-upload/server/content/files/1606e3e25b2c44---pogines.pdf In PDF document text
    • https://callhfelectric.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f16f5070e17---82282375406.pdfIn PDF document text
    • https://maxim-catering.de/wp-content/plugins/super-forms/uploads/php/files/o142ks2a3nrne7a6c7pbcd1ojn/zuterorinuw.pdfIn PDF document text
    • http://payassistinc.com/wp-content/plugins/formcraft/file-upload/server/content/files/16099d0509ec96---pigifawifozumegixegezekux.pdfIn PDF document text
    • https://postelezmasivu-olomouc.cz/ckfinder/userfiles/files/60566809336.pdfIn PDF document text
    • https://actaviaserica.org/board/file/files/pepabitewelomijumonev.pdfIn PDF document text
    • http://geyikkimya.com/userfiles/upload/file/19218950312.pdfIn PDF document text
    • https://www.ideakliniksisli.com/wp-content/plugins/formcraft/file-upload/server/content/files/16083d8ef5172e---wulilizudiwenuxufatas.pdfIn PDF document text
    • http://fashioneducation.ru/userfiles/file/zekozek.pdfIn PDF document text
    • http://nek.ua/wp-content/plugins/formcraft/file-upload/server/content/files/16082c29479bc9---mijubitaza.pdfIn PDF document text
    • http://tai-group.com/upload/files/duzepo.pdfIn PDF document text
    • https://estduquebec.com/scripts/php/xenocode/lib/ckfinder/userfiles/files/94341372262.pdfIn PDF document text
    • https://kassa-evotor.ru/wp-content/plugins/super-forms/uploads/php/files/9rnl7dg3dbhncdtuml1obsd6ml/nenebuvib.pdfIn PDF document text
    • https://asesoriagade.com/app/webroot/files/files/5790539449.pdfIn PDF document text
    • https://impariant-club.ru/wp-content/plugins/super-forms/uploads/php/files/4148055c12b98faec1acbe35c5492450/bozigeridozowizinolepobe.pdfIn PDF document text
    • https://accu-split.com/userfiles/files/periwaliz.pdfIn PDF document text
    • https://aprilboya.com/userfiles/file/jopokavaginisagozigidi.pdfIn PDF document text
    • http://immobilieninvestors.de/userfiles/file/55580160584.pdfIn PDF document text
    • http://ackerviewguesthouse.com/userfiles/file/debaduvozotuvaxuv.pdfIn PDF document text
    • https://beldaoyun.com/calisma2/files/uploads/gasalonixoju.pdfIn PDF document text
    • http://www.aluvascientific.com/UserFiles/file/2622993416.pdfIn PDF document text
    • https://mytutr.com/wp-content/plugins/super-forms/uploads/php/files/cf045ac31da6260313dc31a12ef14834/zanupunokapokuxunuluka.pdfIn PDF document text
    • http://temple.mo/userfiles/file/76945300579.pdfIn PDF document text
    • https://www.azembay.com/wp-content/plugins/super-forms/uploads/php/files/6e1qtm2elhccmgqt5k9962l3sq/ropokugaxugerojenuratis.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/fzgW7-mxBc0/uplcv?utm_term=past+papers+questions+and+answersPDF 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_off0000ef66.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF66 17872 bytes
SHA-256: 65d2cae55d6ee6bd7bb79a0bb86ba2d77e3d395f2caa261393f35b5dc427c9b0
font_01_sfnt_off00011e1a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E1A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00013631.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13631 10672 bytes
SHA-256: 4d72138f1e91a3a0e2ef098eeb4a9e3f5a081921fc697e15fc2f15c4ab9ba317

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