Malicious PDF — malware analysis report

Static analysis result for SHA-256 a26a921fbd563028…

MALICIOUS

PDF

70.9 KB Created: 2021-09-23 07:51:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 11c6c41646b0764cb883d7ab14982c4b SHA-1: 39ef91e4b0f29ea9f089a75fcf0a9865b50e47f4 SHA-256: a26a921fbd563028d0c1e6be3735753421a31428a36ed31910d8d8bb9ac8fdeb
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is a PDF identified as malicious by ML classifiers and ClamAV, with heuristics indicating it functions as a link farm. Several extracted URLs point to compromised CMS upload directories, suggesting an attempt to host or distribute malicious content. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics strongly supports a phishing or malware distribution vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://www.startservis.sk/novy/ckfinder/userfiles/files/47467810842.pdf In PDF document text
    • http://studiospazioambiente.it/userfiles/files/19033950775.pdfIn PDF document text
    • http://langeline.com/ckeditor/upload/files/30833310341.pdfIn PDF document text
    • https://fokusmedia.com/images/uploads/15676957834.pdfIn PDF document text
    • http://megamento.com/_UploadFile/Images/file/52821128465.pdfIn PDF document text
    • http://www.lentilles-progressives.fr/wp-content/plugins/formcraft/file-upload/server/content/files/161344e2d522da---nigixenavi.pdfIn PDF document text
    • http://sieckultury.pl/wp-content/plugins/super-forms/uploads/php/files/6dcec44886acdc9d916a54379ea10a72/65478665990.pdfIn PDF document text
    • http://nhakhoanhantin.com/media/ftp/file/mumuxefumokodet.pdfIn PDF document text
    • https://mobilaide.com/upload/editor/file/50905069675.pdfIn PDF document text
    • http://exactblue.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614247cd528de---8316254694.pdfIn PDF document text
    • http://watch62.ru/files/files/zezobixobunojakovejad.pdfIn PDF document text
    • http://wksystems.net/HotelEstimator/userfiles/file/6161151143.pdfIn PDF document text
    • https://relans-nn.ru/images/docs/file/xuxivepixafakazijob.pdfIn PDF document text
    • https://wilsonbarrera.com/inicio/wp-content/plugins/formcraft/file-upload/server/content/files/1613f34d33d509---75531979696.pdfIn PDF document text
    • https://www.tahitotfalu.hu/ckfinder/userfiles/files/54702810840.pdfIn PDF document text
    • http://colorsoftexas.com/ckfinder/userfiles/uploads/dexafapawiro.pdfIn PDF document text
    • http://travelshops.pl/userfiles/file/jedetivibikuremefolalijor.pdfIn PDF document text
    • http://freemansphotography.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614b7a9627368---ruzepolamekiwopukilosukup.pdfIn PDF document text
    • http://haithuanphat.com/uploads/files/sinijogupixisexoko.pdfIn PDF document text
    • http://jingkangchem.com/upload/files/xukumotixifagevijepabasix.pdfIn PDF document text
    • https://tonwen.org/userfiles/file/tuxivevibiva.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/S30rS-6n6vg/uplcv?utm_term=pokemon+black+2+japanese+romPDF 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_off0000b387.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB387 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cb99.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB99 16416 bytes
SHA-256: 0e1a4a223d711de6fae6483a118f2365d4b9a0996019002a70bc1abe3a2a9a22
font_02_sfnt_off0000f5ff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5FF 10828 bytes
SHA-256: df6feb2facaf56f681f246dc672eeacd4c0f29e47e3fbec0c76aa8f6450eb4bd