Malicious PDF — malware analysis report

Static analysis result for SHA-256 35090a51a7b83f67…

MALICIOUS

PDF

80.8 KB Created: 2021-09-05 06:22:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 571d3c2bd861ea47de39b59df94b2d8c SHA-1: 9a742a404ff33ea002a4d6aac9bc3f9c70cbb8a1 SHA-256: 35090a51a7b83f674851449030bf240129c27049019c1828885091659ac91c51
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 ML classifiers and ClamAV. It functions as a link farm, containing numerous embedded URLs that point to compromised WordPress sites and disposable hosting domains. These links likely serve as lures for phishing attacks or to distribute further malware. The presence of multiple links on potentially compromised infrastructure suggests a broad distribution effort.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

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://skiflogistics.ru/userfiles/file/suladenojorewobij.pdf
    • http://www.gcsystem.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160846ccf81c44---5613763719.pdf
    • http://prplus4u.com/ckupload/files/voxodogotuzomamo.pdf
    • http://langeline.com/ckeditor/upload/files/75954850239.pdf
    • https://www.projectorrentals.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607d7f5909ec9---76766010235.pdf
    • https://ateneoarbonaida.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609b7d089d097---92383752833.pdf
    • http://amirafouad.com/uploaded_files/file/98991405296.pdf
    • http://zaun-produzent.de/userfiles/file/sowusexazatav.pdf
    • http://studiolegalezullo.eu/userfiles/files/jokonisa.pdf
    • https://tourpon.kr/FileData/ckfinder/files/20210616_E2E3C92186E683E8.pdf
    • https://fuze-pay.com/ckfinder/userfiles/files/76173978050.pdf
    • https://koetec.com/home/~ptow/public_html/ckfinder/userfiles/files/38825534872.pdf
    • http://mlsy.cz/images/file/files/32835364326.pdf
    • http://sport-jicin.cz/dokumenty/bisanumibatazagafunub.pdf
    • http://chnli.tw/CKEdit/upload/files/jokodozatakaminevalurupip.pdf
    • https://www.d-table.com/wp-content/plugins/super-forms/uploads/php/files/2d16e1bfc8f15315213f0c4f3894b9d8/89939641989.pdf
    • http://xn--299akc5b432k2sev7g.com/FileData/ckfinder/files/20210704_D3E399FA9DE95501.pdf
    • https://bentzendesign.se/wp-content/plugins/formcraft/file-upload/server/content/files/160c7a8a9d8769---76951043420.pdf
    • http://busto-wl.gattinonimondodivacanze.it/themes/userfiles/files/3272157245.pdf
    • http://nd-58.ru/wp-content/plugins/super-forms/uploads/php/files/654c7be5a3a7796bed01afa0a377adfb/rusitozusurupiferip.pdf
    • http://aceonlinementors.com/userfiles/file/pubanimamuvenupev.pdf
    • https://www.burit.net/wp-content/plugins/formcraft/file-upload/server/content/files/160818d8b827ba---51160932411.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/DOqCt-cVA4I/uplcv?utm_term=tp+link+td-8816+adsl2%2B+modem+router+manual
    • 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_off0000d16a.bin
e2c041ecd66dc20add4b22f790b92c19e24fb9fa9347cccf5f8f7c3cebb2bdbf
pdf-font-stream PDF embedded font (sfnt) at offset 0xD16A 11292 bytes
font_01_sfnt_off0000ec0d.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xEC0D 16792 bytes
font_02_sfnt_off0001041f.bin
6d3ef6f9c9e6ffe32cd5cbdc9c91756901ac1e93c48e0cfc4e4828f3d28b4862
pdf-font-stream PDF embedded font (sfnt) at offset 0x1041F 19028 bytes