Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b9dfb0d36958f91…

MALICIOUS

PDF

87.8 KB Created: 2021-08-25 14:08:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 1393856ace6311f18c12565fd5b635fc SHA-1: a796897e08725a4e2d27a19b6b846f5c899ecf0b SHA-256: 4b9dfb0d36958f91bd553207e6747afe782c4628448e2205b843783a0208d81c
156 Risk Score

Malware Insights

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

The sample is a PDF file identified as malicious by ClamAV and an ML classifier. It contains numerous external links, with several pointing to compromised WordPress upload directories, indicating a potential phishing or spamming campaign. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic suggests it's part of a link farm strategy, likely for SEO manipulation or to distribute malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

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 http://hnfhdc.com/UpLoadFile/2021082314132233778.pdf
    • https://strategieb2b.ca/userfiles/file/22414335574.pdf
    • https://ourcampuswindow.com/ckfinder/userfiles/files/80615454556.pdf
    • https://www.lumisolar.pe/wp-content/plugins/formcraft/file-upload/server/content/files/161154b0737176---venod.pdf
    • https://semsaesp.com/ckfinder/userfiles/files/burakuvitexu.pdf
    • https://baatco.com/ckfinder/userfiles/files/jomujodun.pdf
    • http://jnnycc.org/userfiles/file/rixuduxule.pdf
    • http://conservationenergy.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608ecda4b128b---xikibevakixadezo.pdf
    • http://gattoneva.pl/pages/userfiles/file/8089044227.pdf
    • http://eia-edu.com/userfiles/file/saromewiwenavar.pdf
    • https://hoakhanh.vn/uploads/image/files/12179503043.pdf
    • http://nhatrangpalace.net/app/webroot/upload/files/vanoluzex.pdf
    • http://banglatalkies.com/dynamic-images/cms/file/54912850600.pdf
    • https://alfa-pechati.ru/wp-content/plugins/super-forms/uploads/php/files/2e5df30034e11e03f93f3c4763bc5f7f/winuza.pdf
    • https://kham.vn/userfiles/file/kelefefavusaditobod.pdf
    • http://smartcookieacademy.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609420eca590d---jufuvuporuw.pdf
    • https://keepingscore.org/userfiles/file/sekotujowejik.pdf
    • http://byecook.com/ckupload/files/sawobogevixikikakiduza.pdf
    • https://almondzwealth.com/administrator/imagetemp/file/8170952039.pdf
    • https://www.esfa.bg/root/ckfinder/userfiles/files/xabegaro.pdf
    • http://cesurmakina.com/userfiles/file/radiwubukovudinido.pdf
    • http://www.medicellbank.com/userfiles/files/33208182787.pdf
    • https://gpagroup.in/wp-content/plugins/formcraft/file-upload/server/content/files/160983d1a36947---tepurubabu.pdf
    • http://yangpupark.com/uploadfile/files/31209245828.pdf
    • https://amirep.com/wp-content/plugins/super-forms/uploads/php/files/cd0ca7d299ceb560ea23d2b398936f91/xuseje.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/LPIa9PGmDLg/uplcv?utm_term=physics+chapter+motion+class+9+notes
    • 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_off0000f4d8.bin
35eb79e359a7ffd9a06d63b560d679ff82749c8aa132eeebbbb5c4103071224c
pdf-font-stream PDF embedded font (sfnt) at offset 0xF4D8 16452 bytes
font_01_sfnt_off00011fd7.bin
a9f9caee2b5d0078e814a972f128b43170ce0795c6c86296ec9c01b7fe2f8f11
pdf-font-stream PDF embedded font (sfnt) at offset 0x11FD7 10924 bytes
font_02_sfnt_off0001390c.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x1390C 16792 bytes