Malicious PDF — malware analysis report

Static analysis result for SHA-256 fdf8095343a7b298…

MALICIOUS

PDF

87.2 KB Created: 2021-08-21 11:46:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: ab0da83af567f7ceed1bb6410e4987c3 SHA-1: 542c95a9140fbfab81660a1d34af3e132fcca915 SHA-256: fdf8095343a7b298c63fd872b57c1f6e41d514a7ce9a966238674252d5fd5b22
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file contains numerous external links, many of which point to other PDF files hosted on various domains. Several heuristics indicate this is a link farm, with some links pointing to compromised CMS upload storage. The ML classifier and ClamAV detection strongly suggest malicious intent, likely to manipulate search engine results or distribute further malware. No scripts were extracted, and the document body was unreadable, but the URL structure and heuristic firings are sufficient to assess the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9987

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://k-yoga.org/file_upload/spaw_upload/file/20210718093138.pdf
    • http://begemot-rus.com/uploadfiles/file/2021050303092673499.pdf
    • https://mbzl-pro.xyz/web/img/podborky/files/72458302420.pdf
    • http://techbis.pl/files/file/buwixofopevonufuguje.pdf
    • https://rzfmuhasebe.com/userfiles/file/mavaxubogonapuso.pdf
    • http://szkolka-wiercioch.pl/files/file/zibum.pdf
    • http://huile-de-nigelle.info/userfiles/file/11186648644.pdf
    • http://perfectthesale.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607fc4a83bb62---41775433693.pdf
    • https://itacademyindia.com/ckfinder/userfiles/files/73308320044.pdf
    • https://santa.sg/images/users/00000000/files/zejuxugavalolutalomivu.pdf
    • http://counterreaction.net/wp-content/plugins/formcraft/file-upload/server/content/files/160b5610f3fe8f---24161416418.pdf
    • https://perfecthospitals.org/ckfinder/userfiles/files/rufuniwawuku.pdf
    • http://eastendmediation.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/78718177398.pdf
    • http://www.radiopopiatej.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608c4ff530543---14289490090.pdf
    • http://europeanprofservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/16094c96da46be---65930546381.pdf
    • http://fotografiafrancescosomma.com/userfiles/files/remud.pdf
    • https://motty-etai-sharon.com/files/files/78469074564.pdf
    • http://www.naturapreserved.com/wp-content/plugins/formcraft/file-upload/server/content/files/16078bf797a3aa---30710101525.pdf
    • http://highlandhighclassof1962.com/clients/c/c3/c330a44b04b080977bf299ea430a317d/File/bukowusotesewe.pdf
    • https://gagiongvitgiong.com/ckfinder/userfiles/files/64691723629.pdf
    • https://bykevin.com/wp-content/plugins/super-forms/uploads/php/files/224774fed766bc75e49d771cd96eccab/simuvabodubaxurowi.pdf
    • http://henri-ruch.ch/doc_pub/file/88557448560.pdf
    • http://rafaelokazakov.com/file/39450109283.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/6naE_Nh8_CY/uplcv?utm_term=age+of+empires+2+hd+lan
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000eead.bin
1d45ce757d138e23e73d4239e0080e9ea5e6c711cbd30e3b9d21b9ece629ec0c
pdf-font-stream PDF embedded font (sfnt) at offset 0xEEAD 10948 bytes
font_01_sfnt_off000107a8.bin
b6d27fc6c6f1580d27b4e96a1aa2d3d6b8a1e9284436c78097a69795a23502cb
pdf-font-stream PDF embedded font (sfnt) at offset 0x107A8 17932 bytes
font_02_sfnt_off00013662.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x13662 16792 bytes