Malicious PDF — malware analysis report

Static analysis result for SHA-256 81bb497bde2b1ad4…

MALICIOUS

PDF

87.3 KB Created: 2021-08-14 03:52:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 0b71c4b3fc88c4e5bd936f0e95726ac2 SHA-1: c53c0ac44d0894281e9aa88a25a5293c0e7f76b4 SHA-256: 81bb497bde2b1ad4e33d0be8d45dbdd951542e51f41dab408ef6da545901708f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It functions as a link farm, with numerous embedded URLs pointing to compromised CMS uploads and disposable hosting, suggesting an attempt to redirect users to malicious sites. No scripts were extracted, but the PDF structure and embedded URLs are indicative of a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://www.ferienhof-schneider.de/wp-content/plugins/formcraft/file-upload/server/content/files/1611398311f3c6---likur.pdf
    • http://bookblog.kr/data/file//files/69433653255.pdf
    • http://drapikowski.pl/uploaded/fck_files/file/23762449833.pdf
    • https://www.clubmanizales.com.co/wp-content/plugins/formcraft/file-upload/server/content/files/160fbd0bc5eb87---juliparox.pdf
    • https://www.marbelitesa.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160b50f8ac0093---88622881931.pdf
    • http://hoadon-dientu.net/images/files/tinifuniboki.pdf
    • http://www.k-24.com/wp-content/plugins/formcraft/file-upload/server/content/files/160861cbf59f16---dimofixat.pdf
    • http://clubsahdianagalati.ro/upload/editor/file/valivipom.pdf
    • http://ildungrice.com/fileupload/fckeditor/file/55604637759.pdf
    • http://cathyknightwaite.com/ckfinder/userfiles/files/dilagoxorefolase.pdf
    • https://nonbodepsg.com/uploads/files/luxase.pdf
    • http://asckhn.com/acskhn/userfiles/file/bitowatotevizadelara.pdf
    • https://smobiil.eu/userfiles/files/20768003826.pdf
    • http://geobrofab.com/clients/d/da/da7cd3953015cd63472398095fc1fcdd/File/gurotimonisivolewosi.pdf
    • https://www.idahomedia.com/wp-content/plugins/super-forms/uploads/php/files/7d581079f631b3a1c51e36cee948fc9c/51490535494.pdf
    • http://camelliafb.com/uploads//files/202108051042424704.pdf
    • http://bridgesonthepark.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d969cc03d3c---31812212447.pdf
    • https://legacyltg.com/wp-content/plugins/super-forms/uploads/php/files/e311f3cdace0d7c171093b6abfb36696/wibemimokutafitogo.pdf
    • http://www.jamesbgriffinlaw.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607804d518072---bokisuxoxowus.pdf
    • http://satakantaresort.com/user_img/files/77395605658.pdf
    • http://ahs1968.com/clients/d/dc/dcea35c349c70fb55dca458fc6558ff6/File/junigevidawo.pdf
    • https://braintreeclinics.com/app/webroot/img/files/5078121047.pdf
    • http://www.nuricomuvakfi.org/wp-content/plugins/super-forms/uploads/php/files/v003270p5h1u6eb225hoqa74d7/32332431354.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=diagn%C3%B3sticos+de+enfermer%C3%ADa+nanda+pdf+2019
    • 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_off0000e959.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xE959 16792 bytes
font_01_sfnt_off0001016b.bin
e421c8d8dc1d86395ca995a04c56736a7cfee5e3c7e27a0bba48947b08f15e71
pdf-font-stream PDF embedded font (sfnt) at offset 0x1016B 19020 bytes
font_02_sfnt_off000131cf.bin
7d185850690a2ee295250211a0a82f3593c51eecc5f632f6a33c895a299326d7
pdf-font-stream PDF embedded font (sfnt) at offset 0x131CF 11580 bytes