Malicious PDF — malware analysis report

Static analysis result for SHA-256 b37df4402162b9e3…

MALICIOUS

PDF

82.0 KB Created: 2021-08-08 11:17:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 888d6163b514230eedc3ec30b1e2dfe7 SHA-1: 2ba8e17f89b472815eb53101f7f1afbc0f2a2dea SHA-256: b37df4402162b9e3470ec54a485f1df6d45d823fb5d878c6d58a5d83af5ea56d
156 Risk Score

Malware Insights

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

The PDF contains a link farm pointing to multiple compromised WordPress upload directories, indicating a phishing or malware distribution attempt. The ML classifier and ClamAV detection strongly suggest malicious intent. The document body is heavily obfuscated and appears to be metadata from the wkhtmltopdf tool, providing no direct user-facing content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://vvpta-irvine.org/userfiles/file/wekisovefurijage.pdf
    • http://frigotechreina.com/userfiles/files/60246213206.pdf
    • http://hndgyl.com/v15/Upload/file/20216222128466802.pdf
    • http://www.davidwoodpersonnel.com/wp-content/plugins/formcraft/file-upload/server/content/files/160db9bcff2135---61222737842.pdf
    • http://www.commandinglife.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bb9fc1c5abd---dexezedubomakobufa.pdf
    • http://sl-light.ru/design/img/upload/file/77525439594.pdf
    • http://pattarasawat.com/ckfinder/userfiles/files/16930420099.pdf
    • https://hacunamatata.ru/wp-content/plugins/super-forms/uploads/php/files/b0d9a1bb38a2326ece4d5bcb1b82f2a2/wivexonepozuro.pdf
    • https://terravistahometeam.com/wp-content/plugins/super-forms/uploads/php/files/aafdecd660b19785e1bd655af9c42ee1/30901956383.pdf
    • http://hccc252.ca/clients/e/e4/e484b38507f190a955b66748903449e1/File/8843632654.pdf
    • https://indacphuc.com/wp-content/plugins/super-forms/uploads/php/files/hfqvh2n9ks4c30mpnp4iglnag2/36323719853.pdf
    • https://razvozka24.ru/wp-content/plugins/super-forms/uploads/php/files/3a912fda19176e562e42f594d290d231/98128535376.pdf
    • http://sbsinternationalschool.org/sbsisnew/userfiles/file/dewowaxusu.pdf
    • http://fabiocaronearchitetto.com/userfiles/files/fifonojux.pdf
    • http://neilreardon.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/81369866211.pdf
    • http://villa-carlshorst.de/sites/default/files/file/45703297047.pdf
    • http://ipsgroupjjn.org/userfiles/file/vixodu.pdf
    • http://nextgenship.net/upload/file/20210519162141569625.pdf
    • http://pck.malopolska.pl/wp-content/plugins/super-forms/uploads/php/files/8a6855b1d77a3e0c217e50a46bd4a27e/xekijuvomimoni.pdf
    • https://www.die-umzugsfabrik.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b4527381b28---rolavokabomemujawowuwini.pdf
    • https://cdpu.net/wp-content/plugins/super-forms/uploads/php/files/efb7e7599d6ad7ded1c0d2f09de1e049/22902493304.pdf
    • http://becro-plast.hr/wp-content/plugins/formcraft/file-upload/server/content/files/160c75298cd24d---45619606280.pdf
    • https://yarsan.ru/wp-content/plugins/super-forms/uploads/php/files/b3db4243224f8d6e3bdea94d047543b4/55521233464.pdf
    • http://grupogmec.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c333e08c5ae---78672606395.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=how+to+refill+my+turbo+blue+torch
    • 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_off0000db41.bin
77ea36471f35fcc4657a6bbc7d8277ce4ebd33524c0660a7206120c99f605325
pdf-font-stream PDF embedded font (sfnt) at offset 0xDB41 10596 bytes
font_01_sfnt_off0000f377.bin
e306472d46dbc9711b3449b4d224421bd4f927dfbc8ab73fdc0953dd581b7514
pdf-font-stream PDF embedded font (sfnt) at offset 0xF377 18056 bytes
font_02_sfnt_off0001226c.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x1226C 16792 bytes