Malicious PDF — malware analysis report

Static analysis result for SHA-256 81ce272a5fba126b…

MALICIOUS

PDF

71.5 KB Created: 2021-09-26 04:32:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 8454d4b86123de8b5e15643b82200668 SHA-1: efc48638afa0b625739bdb38704f45c8a05b1ab7 SHA-256: 81ce272a5fba126ba73456e322d7539dc2382ff402eaa92c0f8a1ba1c8edc800
156 Risk Score

Malware Insights

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

The PDF contains numerous external links, many pointing to compromised CMS upload storage or disposable hosting, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware delivery. The presence of multiple PDF-specific heuristics related to URI and link farms supports this conclusion.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

Heuristics 6

  • 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.
  • 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://smidgel.ru/uplcv?utm_term=ultimate+bike+simulator PDF link annotation
    • http://korea-labels.com/ckfinder/userfiles/files/10251750464.pdfIn PDF document text
    • https://millinerandassoc.com/files/file/pamunabuned.pdfIn PDF document text
    • http://viviapalermo.com/userfiles/files/sejaxuma.pdfIn PDF document text
    • http://dansungsala.com/uploads/files/sajitoradese.pdfIn PDF document text
    • http://dogable.de/userfiles/file/dumuresegukabit.pdfIn PDF document text
    • https://fiscalonline.eu/app/webroot/files/userfiles/files/xotaputapelusukarujagejoj.pdfIn PDF document text
    • https://www.dyna-tech.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16133b6534e850---30910461764.pdfIn PDF document text
    • https://nepaltrekkinginhimalaya.com/assets/userfiles/files/wikumup.pdfIn PDF document text
    • https://perfecthospitals.org/FCKeditor/file/95904116403.pdfIn PDF document text
    • https://rcot.org/userfiles/file/butubosuduvaribagibad.pdfIn PDF document text
    • http://szentdorottyapatika.hu/files/92263391697.pdfIn PDF document text
    • http://pietrek.com/MARCUS/files/file/bojuxufojolo.pdfIn PDF document text
    • https://primer-spb.ru/files/files/7792076292.pdfIn PDF document text
    • http://kingkady.cn/uploadfile/files/40494912648.pdfIn PDF document text
    • http://nitexprofi.cz/userfiles/file/91086215169.pdfIn PDF document text
    • https://zifu-tech.com/app/webroot/userfiles/files/17462553558.pdfIn PDF document text
    • http://osullivanspressurewashing.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612feef2e3af7---48828623389.pdfIn PDF document text
    • http://decamiones.com/userfiles/file/kosesi.pdfIn PDF document text
    • https://www.grandeprairie.org/wp-content/plugins/formcraft/file-upload/server/content/files/1613d94952ac08---fazare.pdfIn PDF document text
    • http://anthonyjcincottalaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/ratuvad.pdfIn PDF document text
    • https://khanoomhoteli.com/basefile/khanoomhotelicom/files/nadononisupikagolegit.pdfIn PDF document text
    • http://markone-tools.com/upload/files/88651007980.pdfIn PDF document text
    • http://satcomlink.com/userData/board/file/mazavir.pdfIn PDF document text
    • http://gsmontaggi.it/userfiles/files/zesebufa.pdfIn PDF document text
    • http://naasschoolofmotoring.ie/fckeditor/userfiles/file/36120999894.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://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_off0000b322.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB322 17992 bytes
SHA-256: a536cbfef6880475dfdb7050559747b6215f9405e19da682601ef8625d201344
font_01_sfnt_off0000e0aa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE0AA 10504 bytes
SHA-256: e85846809826e4fb035c712e05ccae7f895bf086cb47c48919ce95235226f20b
font_02_sfnt_off0000f898.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF898 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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