Malicious PDF — malware analysis report

Static analysis result for SHA-256 88a6c30700e76e54…

MALICIOUS

PDF

77.7 KB Created: 2021-09-03 11:33:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 211b8206b20631e9ba4cf858e183285b SHA-1: 531762d0210efac18ac1dc5a8b83647971782647 SHA-256: 88a6c30700e76e5485aa95989b6aa40609aa6bcb44ff3f9cae972b4cc452e1ad
164 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous URLs, some pointing to compromised CMS upload storage, suggesting it functions as a link farm or a lure for downloading further malicious content. The presence of a 'download button' heuristic further supports the attack pattern of tricking users into downloading a payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://amthanhanhsangchinhhang.vn/upload/files/rumem.pdf In PDF document text
    • http://dhsclassof70.com/clients/d/d1/d13f49183e6b2ef720c1f353b43de0f2/File/tusigakulu.pdfIn PDF document text
    • https://tehnol.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1609bffdc064f0---nujasawemirefijuwiniza.pdfIn PDF document text
    • http://angeladaniel.eu/uploads/files/barowagevepobinebali.pdfIn PDF document text
    • http://www.fliesen-brill.de/wp-content/plugins/formcraft/file-upload/server/content/files/16071d0183c10e---95538693535.pdfIn PDF document text
    • http://reicar.dk/userfiles/file/vojuronal.pdfIn PDF document text
    • http://dogninja.com/userfiles/files/97362989983.pdfIn PDF document text
    • http://ampletrekking.com/userfiles/file/dodizasaginerumosefuraf.pdfIn PDF document text
    • http://cestovni-postylka.eu/userfiles/file/pilazupevutunokulawebun.pdfIn PDF document text
    • http://nd-58.ru/wp-content/plugins/super-forms/uploads/php/files/1bb33ea77da727099783446982e57e97/50351061436.pdfIn PDF document text
    • https://www.digitalsofts.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c311c3757a0---53492518009.pdfIn PDF document text
    • https://kfz-gutachter-oliver-schiller.de/wp-content/plugins/formcraft/file-upload/server/content/files/16079425dabb72---raxukivopidirupoduva.pdfIn PDF document text
    • http://maxitelt.no/wp-content/plugins/formcraft/file-upload/server/content/files/160c3d1182592d---6516164847.pdfIn PDF document text
    • https://bechtoldpaving.com/wp-content/plugins/super-forms/uploads/php/files/935cb268bb45aa7453d068d01b863db2/52765573366.pdfIn PDF document text
    • https://www.mnspineandsport.com/wp-content/plugins/super-forms/uploads/php/files/fc2911cdcad3f3d3ae2af3a267458235/narutazafererupukepipe.pdfIn PDF document text
    • https://daleplumbinginc.com/wp-content/plugins/super-forms/uploads/php/files/c10a27f3fc0f272ab9f93f22e56a3811/24717745755.pdfIn PDF document text
    • https://biocoop.legreniervert.fr/ckfinder/userfiles/files/wizudenezu.pdfIn PDF document text
    • https://www.frontierexim.com/wp-content/plugins/super-forms/uploads/php/files/0i6nda9mnnldu8ct0uhjdvb89b/15236341243.pdfIn PDF document text
    • http://pincailight.com/zk/UploadFile/file/2021082112144373499.pdfIn PDF document text
    • https://isosklo.cz./uploads/18562336135.pdfIn PDF document text
    • http://insfilings.com/skyzone_classic/upload/files/ritixefasozudawawazoji.pdfIn PDF document text
    • http://kozszemle.hu/uploads/files/mabeletudunarewur.pdfIn PDF document text
    • http://www.guaitoli.eng.br/wp-content/plugins/formcraft/file-upload/server/content/files/16072d2f612911---wilemenabumufotoda.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BvfzZFkJO3s/uplcv?utm_term=twitter+bootstrap+tutorial+pdfPDF 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_off0000cdea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCDEA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e5fc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE5FC 16740 bytes
SHA-256: 155dcb6a9b8f80747da5ea0b2f6e98300bbbd9c16d04c57e2901354badc5d69b
font_02_sfnt_off000110b1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x110B1 10676 bytes
SHA-256: 0560f527d7d7fa0caf2afe79e207dd03d2f641d852319f9af6b2ef93c47aa7ea

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