Malicious PDF — malware analysis report

Static analysis result for SHA-256 1bf96b8679211697…

MALICIOUS

PDF

81.0 KB Created: 2021-10-18 09:47:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: c1dbf97831cf2dd03e8692d5dfe7bb13 SHA-1: a7115fa66069d8e7800fae9f4ccebb145b4a8a3e SHA-256: 1bf96b8679211697db132df7f5460d8f6a29ecff8c4da138572d53c6244bd37e
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous links pointing to external PDF files hosted on various domains, many of which appear to be disposable or compromised. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The document body is heavily obfuscated and contains metadata from wkhtmltopdf, suggesting it was generated programmatically rather than being a user-facing document.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9917

Heuristics 6

  • 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.
  • 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://kimsanghun.com/upload/userfiles/file/20211062353230059.pdf In PDF document text
    • http://kingsap.com/file_media/file_image/file/gidor.pdfIn PDF document text
    • http://bertrandetgastineaudesigners.com/userfiles/file/72349224820.pdfIn PDF document text
    • https://maconlux.ovh/userfiles/files/jodusubulagerir.pdfIn PDF document text
    • http://tea-ra.com/user_data/upload/save_image/files/66948377061.pdfIn PDF document text
    • http://ilkjv.com/Images/Media/files/mogepawor.pdfIn PDF document text
    • https://cytairtool.com/test/userfiles/file/20210928_b1eee.pdfIn PDF document text
    • http://chingyi.tw/userfiles/files/45495802290.pdfIn PDF document text
    • https://thriveelearning.com/wp-content/plugins/super-forms/uploads/php/files/fac28ac1a4629bfe73628ba4a461956c/26443780447.pdfIn PDF document text
    • http://maidichike.com/upload/files/jezaneset.pdfIn PDF document text
    • https://maribon.net/app/webroot/files/userfiles/files/parufu.pdfIn PDF document text
    • https://www.bevillelecomte.com/ckfinder/userfiles/files/36142577955.pdfIn PDF document text
    • http://koreabulk.net/userData/board/file/90603895027.pdfIn PDF document text
    • http://moscowfashion.net/content/xuploadimages/file/62325391910.pdfIn PDF document text
    • https://studyhalltracker.com/files/file/giboretedezopuvifefofikut.pdfIn PDF document text
    • https://oriental-kitchens.com/userfiles/files/rovufuvifarobenof.pdfIn PDF document text
    • http://physio-praxismitte.de/userfiles/kewuzojuvirotegabig.pdfIn PDF document text
    • http://jamoncup.es/wp-content/plugins/formcraft/file-upload/server/content/files/1615f42f4a9779---murejonilepokegivuromu.pdfIn PDF document text
    • http://synhbio.com/upload/files/79561962742.pdfIn PDF document text
    • http://schubert-hh.de/image/file/zipojupabupasixojiduno.pdfIn PDF document text
    • http://akafgdsgreawy.pretty-match.com/upload/files/45880339044.pdfIn PDF document text
    • http://hepiran.com/cache/fck_files/file/97437582679.pdfIn PDF document text
    • http://www.neslihanonur.com/wp-content/plugins/super-forms/uploads/php/files/7adba9ad4653b7e8f5dd3bb77a01f67a/59419639238.pdfIn PDF document text
    • https://epiphanych.com/images/file/53274581404.pdfIn PDF document text
    • https://vinatech.com/userfiles/file/poxebekiretuserabi.pdfIn PDF document text
    • http://villabrown.it/userfiles/files/73364100517.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Gsjc/~3/EqozwcbAC44/uplcv?utm_term=malnutrition+in+infants+causesPDF 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_off0000d8d2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD8D2 17608 bytes
SHA-256: 16b311ef64cc9442c26b1f81fee7ea150ed62aeefc07dd0f35aa03e65c439a72
font_01_sfnt_off00010639.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10639 10420 bytes
SHA-256: 461ac17081610dfe542f6fd413aefa4d9f69f4fcec0ce703a7f82e0b04068e5e
font_02_sfnt_off00011e00.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E00 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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