Malicious PDF — malware analysis report

Static analysis result for SHA-256 28cf59c8e7bfff1b…

MALICIOUS

PDF

70.9 KB Created: 2021-09-01 14:51:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: d8ae21bf68d8a3e2c6bd041435057fab SHA-1: 9fa3a99bea39e96f3875f3bf038e64a36438718d SHA-256: 28cf59c8e7bfff1bb6920562b05658e2d423b84cbd572a3f6cda5e5bf335afbd
156 Risk Score

Malware Insights

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

The PDF contains numerous links pointing to compromised WordPress upload directories and other disposable hosting, indicating it functions as a link farm. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or distributing further malware. No scripts were extracted, and the document body was unreadable, but the URL structure and heuristic firings are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://nhaban24h.com.vn/wp-content/plugins/super-forms/uploads/php/files/02375g44tsmjcqhon8ns3keoh8/96700157262.pdf In PDF document text
    • https://bem-sa.com/img/file/91282119140.pdfIn PDF document text
    • https://tamtam.com.ua/wp-content/plugins/super-forms/uploads/php/files/7b19aa3466cec86c9d4187a055808d6c/15696892243.pdfIn PDF document text
    • http://alexanderkanevskyartistbiography.com/clientMedia/file/ronotij.pdfIn PDF document text
    • https://ascinfratech.com/clientprojects/trading/file/62925680770.pdfIn PDF document text
    • https://angkagenap.com/contents//files/bupabojojedozuxunanosupi.pdfIn PDF document text
    • http://vodova51-53.cz/files/fotodetigenonotiwalovu.pdfIn PDF document text
    • https://atlas-consulting.ro/fckeditor/fisiere/file/lutef.pdfIn PDF document text
    • http://playfromhome.org/clients/4/49/49939bf6a151252ba1adfe53d1befa29/File/31467028655.pdfIn PDF document text
    • https://eitmedu.in/ckfinder/userfiles/files/66004396130.pdfIn PDF document text
    • https://daluxerealty.com/wp-content/plugins/super-forms/uploads/php/files/dnpmiqdhnifbkkqcui9aa4vb11/sovibakezewipisojikugix.pdfIn PDF document text
    • http://sochi-vitrazhi.ru/ckfinder/userfiles/files/94614331173.pdfIn PDF document text
    • https://adasms.fr/userfiles/file/67934991306.pdfIn PDF document text
    • https://backcountryplayground.com/wp-content/plugins/super-forms/uploads/php/files/b7b102db29a452fe1717c4b939f7736c/bivax.pdfIn PDF document text
    • https://ohligschlaeger-berger.de/wp-content/plugins/formcraft/file-upload/server/content/files/16084cd0d2429e---zumalum.pdfIn PDF document text
    • http://faradtvandor.hu/picture/userfiles/file/8045723902.pdfIn PDF document text
    • https://sitpchemcieszyn.pl/_sitpchem/file/64880986374.pdfIn PDF document text
    • http://recruiters-zone.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609e06b232c13---wepipidosezime.pdfIn PDF document text
    • https://vydavatelstvoklett.sk/userfiles/file/lugusi.pdfIn PDF document text
    • http://kiajihlava.cz/UserFiles/File/vanonewudulopijumore.pdfIn PDF document text
    • http://pocatellocampfire.com/wp-content/plugins/super-forms/uploads/php/files/nuth34j2ucsvtu25m5jq8p4imj/41475544702.pdfIn PDF document text
    • https://coloreverything.love/wp-content/plugins/super-forms/uploads/php/files/8494967412ce268ad1545c039286bf1b/17339934986.pdfIn PDF document text
    • http://universe-micro.com/upload/files/20210703_120410.pdfIn PDF document text
    • http://aelma.com/sites/default/userfiles/file/ratudupibuxuke.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/6naE_Nh8_CY/uplcv?utm_term=one+pint+equals+ouncesPDF link annotation
    • 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_off0000b508.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB508 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cd1a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD1A 16176 bytes
SHA-256: 6a3f6aab5e6339b7ee78357a01ab41f58ee3d796c144246c6a952fe71677a0c9
font_02_sfnt_off0000f60f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF60F 10536 bytes
SHA-256: 63f9b17d77ed9523f6c1f785b050a627847c0f3e2fa0d67d85d5c21adee08da7