Malicious PDF — malware analysis report

Static analysis result for SHA-256 55a77c63ee3f5b3a…

MALICIOUS

PDF

84.9 KB Created: 2021-09-16 02:48:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 46161cde0782142558c5c7c1651fe604 SHA-1: 75767f37fd7c604020a4075f393cc28febc5a455 SHA-256: 55a77c63ee3f5b3add9182d4972e59a5b7c8f9ba35005ab7960d7f79f1dfdf27
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was identified as malicious by ML classifiers and ClamAV, with multiple heuristics indicating it functions as a link farm pointing to compromised WordPress uploads and disposable hosting. The embedded URLs suggest a phishing or malware distribution scheme, likely initiated via spearphishing. No scripts were extracted, but the PDF structure and URL patterns are indicative of malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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://crysiq.ru/uplcv?utm_term=menyoo+online+download PDF link annotation
    • http://phannhan.vn/files/usersfiles/files/2087933320.pdfIn PDF document text
    • http://machulski.com/public/file/8889292749.pdfIn PDF document text
    • http://churchliferesources.org/wp-content/plugins/formcraft/file-upload/server/content/files/16136d5a5c4f13---vosibovamobomatowugobopif.pdfIn PDF document text
    • http://kehlux.lu/userfiles/files/53991118411.pdfIn PDF document text
    • http://stensoproject.com/userfiles/files/41053638732.pdfIn PDF document text
    • http://whdhgs.com/uploads/file/20210910185228787.pdfIn PDF document text
    • https://alarrabnews.com/images/content/content/file/8939479714.pdfIn PDF document text
    • https://www.rosebankprimary.co.za/inc/ckfinder/userfiles/files/61568480095.pdfIn PDF document text
    • http://recruiters-zone.com/wp-content/plugins/formcraft/file-upload/server/content/files/16141ae753ebd3---92160820854.pdfIn PDF document text
    • https://newtech-utm.pl/userfiles/file/38605037440.pdfIn PDF document text
    • https://natyabio.com/uploadfiles/8146302743.pdfIn PDF document text
    • http://vps73.juicy-group.com/editor_upload_image/file/mowopusotenafonop.pdfIn PDF document text
    • https://formapolis.it/wp-content/plugins/super-forms/uploads/php/files/2670635f7ebee5a423266273329e761e/89467182380.pdfIn PDF document text
    • https://mimpiindahsatu.com/contents/files/kidomutufekefiwubadiwuxug.pdfIn PDF document text
    • http://steclotildehorton.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1612ff8151a127---63445767011.pdfIn PDF document text
    • http://strojsteel.cz/webpagebuilder/ckfinder/userfiles/files/96315857794.pdfIn PDF document text
    • http://fantasypartyentertainment.com/wp-content/plugins/formcraft/file-upload/server/content/files/161339b1cb7dac---4544258349.pdfIn PDF document text
    • http://britishcytology.org.uk/ckfinder/userfiles/files/minodiwitutuma.pdfIn PDF document text
    • http://tdvvietnam.vn/webroot/img/files/zetud.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_off0000e71b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE71B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ff32.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF32 10068 bytes
SHA-256: 0aaae68fada080df96579a171df551a928d90dcb5f34f4b9274f88a0149c6fc8
font_02_sfnt_off000115bd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x115BD 18780 bytes
SHA-256: 1b89de432a1f8d1bb2afacc76f2f0a5742d5acd3e8905cf01d8fe13492c5e975