Malicious PDF — malware analysis report

Static analysis result for SHA-256 9a87a2d88029865c…

MALICIOUS

PDF

77.3 KB Created: 2021-06-10 00:58:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-25
MD5: 83785b79538c92c5b7c6da4daca46892 SHA-1: 2ba382afbf12a8c0657fc2d1cd53ce31e8ca5042 SHA-256: 9a87a2d88029865c28bb55b677d9cd4f751a250958ce0e0094cbdb1fff4129ec
164 Risk Score

Malware Insights

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

The sample is a PDF file flagged by ML classifiers and ClamAV as malicious. It contains numerous embedded URLs, many of which point to compromised WordPress sites, suggesting a link farm designed to redirect users to malicious content. The document body, though heavily obfuscated, contains text related to downloading a handbook, aligning with the 'SE_DOWNLOAD_BUTTON' heuristic.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://crewmak.ru/uplcv?utm_term=oxford+handbook+of+clinical+medicine+pdf+free+download PDF link annotation
    • https://lisacutler.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ab1c4e12167---96617185372.pdfIn PDF document text
    • http://www.louthadventures.ie/wp-content/plugins/formcraft/file-upload/server/content/files/16075e3ba92fb6---linas.pdfIn PDF document text
    • https://alianzatours.com/imagenes/file/pakis.pdfIn PDF document text
    • https://totalyoumovement.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607be0fbaf114---13421282257.pdfIn PDF document text
    • http://finsura-lifedirect.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1608a03c027003---belovalir.pdfIn PDF document text
    • https://glasschneider.koeln/wp-content/plugins/super-forms/uploads/php/files/qff51ahap927nttiubkiaq6obp/werikab.pdfIn PDF document text
    • http://nensi.si/upload/file/kezofopupogerudapadis.pdfIn PDF document text
    • https://vetranhtuongmamnon.vn/wp-content/plugins/super-forms/uploads/php/files/ustb1b269igialr9popr778lmu/pedabotowomufutex.pdfIn PDF document text
    • http://plenar.hr/wp-content/plugins/formcraft/file-upload/server/content/files/160a2762c93875---24938574238.pdfIn PDF document text
    • https://an-professional.ru/img/files/file/xidawizitalamizobas.pdfIn PDF document text
    • https://action-roofing.com/wp-content/plugins/super-forms/uploads/php/files/668141e4357c7b6f1a6924f1ba6b0c7a/24876563012.pdfIn PDF document text
    • https://lordpin.com/calisma2/files/uploads/45990761061.pdfIn PDF document text
    • http://banghaija.com/userfiles/file/80676336263.pdfIn PDF document text
    • https://www.adcgrain.com/wp-content/plugins/super-forms/uploads/php/files/d96458b2a089284e1e5a689a14abb935/58614395622.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://kioskcondoweb.wpengine.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606e241de9767---24613716810.pdfIn PDF document text
    • 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e692.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE692 5608 bytes
SHA-256: accb58052515613dac951d62382e7a701f169c74f52dbcb2eade6405ff565f7d
font_01_sfnt_off0000f980.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF980 1800 bytes
SHA-256: daad3f347a4f42f432ee9983e619a7c063e36761dba5934b469418034847e28e
font_02_sfnt_off0001020e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1020E 11040 bytes
SHA-256: 0ef46fbba7c0de68b81e93d9946a2af112da29b49f9201d98001a4b192073850