Malicious PDF — malware analysis report

Static analysis result for SHA-256 88372f0d8de06518…

MALICIOUS

PDF

75.5 KB Created: 2021-09-12 12:14:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 597d1154f8e4d697facf250264e816e7 SHA-1: 2f27cd0a1348e8841c99e1c82707ce48aded0a3c SHA-256: 88372f0d8de0651868eb2bfc2bf48d96ab0469f97d0b0194140faf31044dde1f
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which point to PDF files on various domains, suggesting a link farm or redirection mechanism. The 'PDF_SEO_DISPOSABLE_LINK_FARM' heuristic further supports this, indicating the document's purpose is to host many links. While no scripts were explicitly extracted, the nature of the embedded URLs and the heuristics suggest an attempt to direct users to potentially malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 https://syntellect.ru/Repository/file/96444239076.pdf In PDF document text
    • http://nirmalapublicschoolerumely.com/userfiles/file/divemeramuk.pdfIn PDF document text
    • http://sdtrafficticketlawyer.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/zadugisuzaf.pdfIn PDF document text
    • https://www.mppoa.cloudlinesystems.com/assets/ckfinder/userfiles/files/vumufidi.pdfIn PDF document text
    • http://dichvumucin.com/upload/ckupload/files/86411447888.pdfIn PDF document text
    • http://builderall.info/userfiles/file/zupoto.pdfIn PDF document text
    • http://borik.customreal.sk/data/files/kokili.pdfIn PDF document text
    • https://swiz.eu/files/editor/69266907514.pdfIn PDF document text
    • https://shen-su.eu/gfx/userfiles/files/34618916910.pdfIn PDF document text
    • https://enilubricant.hoakhanh.vn/uploads/image/files/77348172069.pdfIn PDF document text
    • https://tonere.shop/app/webroot/files/userfiles/files/77311870687.pdfIn PDF document text
    • https://xn--22ck6bdp5cach0mc23a.com/ckfinder/userfiles/files/benewuzutejosij.pdfIn PDF document text
    • http://hzzxtl.com/UploadFile/file/20210907120511040.pdfIn PDF document text
    • http://okwmd.com/upload/fckeditor/file/punokuruluwoliketebapi.pdfIn PDF document text
    • https://quangcaowebsite.xemlaco.com/uploads/files/pisufuvisekozi.pdfIn PDF document text
    • http://www.aamuhsv-madisonalumni.org/files/files/mirifo.pdfIn PDF document text
    • http://unibox.lv/files/text/dujirogezamek.pdfIn PDF document text
    • http://nnk.gr/wp-content/plugins/formcraft/file-upload/server/content/files/1613997c439d30---gotediwomofobakirepug.pdfIn PDF document text
    • https://markiza-trade.ru/admin/ckfinder/userfiles/files/dividosopagekidogagos.pdfIn PDF document text
    • https://msiutilities.net/documents/54364603549.pdfIn PDF document text
    • https://alev.az/userfiles/file/65108894112.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/6naE_Nh8_CY/uplcv?utm_term=dua+for+my+dad+to+get+betterPDF 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_off0000c132.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC132 10640 bytes
SHA-256: 337656c58970e60823a861c9a167a87075afe901b3ee4e884af0ca76e6400ae3
font_01_sfnt_off0000d96b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD96B 18428 bytes
SHA-256: 488ca362da50705b10815b90e454294c0087ed38880a068b3174f6488a8527cb
font_02_sfnt_off000108f9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x108F9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1