Malicious PDF — malware analysis report

Static analysis result for SHA-256 81bc14c0f18d442c…

MALICIOUS

PDF

80.8 KB Created: 2021-09-18 22:23:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: ceb5cb848c7106e47c8eb6215a96d32c SHA-1: abfbb4bf2e9faa97c217f04019ff00a3fe5addda SHA-256: 81bc14c0f18d442ce5c99d54bbf9ca36f34d3a091fac7e287a7bda9374dd3c00
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 User Execution: Malicious Link

The PDF file contains numerous links to external websites, many of which are hosted on compromised CMS platforms or disposable domains, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware distribution. No scripts were extracted, and the document body was unreadable, so the rationale is based on the URL analysis and heuristic findings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

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://zifu-tech.com/app/webroot/userfiles/files/poxusedipomekoramuli.pdf In PDF document text
    • http://hotelniagararimini.eu/userfiles/files/tinagupaxug.pdfIn PDF document text
    • https://norservis.info/files/files/4229789071.pdfIn PDF document text
    • https://ercrs.org/wp-content/plugins/super-forms/uploads/php/files/ke19ot9lvf7lmi1m92p0gv0ud4/vigebasudujipu.pdfIn PDF document text
    • https://pfgmm.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1613a2a5f4eb8c---wuvuwigotevotik.pdfIn PDF document text
    • http://gongotour.com/FileData/ckfinder/files/20210918_B43876ECF07EC879.pdfIn PDF document text
    • http://belly.bpv.su/content/files/files/24699104826.pdfIn PDF document text
    • http://www.bsa.by/ckfinder/userfiles/files/35200720443.pdfIn PDF document text
    • http://paliukenas.lt/i/File/kugevalag.pdfIn PDF document text
    • https://segurosjdd.com/wp-content/plugins/super-forms/uploads/php/files/gqdu1b8ccimjcr2mlod2cgu1c1/febubaxijod.pdfIn PDF document text
    • https://samuelben-horin.com/userfiles/file/95187628119.pdfIn PDF document text
    • http://nessium.fr/userfiles/file/wesipewilumi.pdfIn PDF document text
    • http://kovofilm.cz/userfiles/file/pidizazuvoxomerijatupipos.pdfIn PDF document text
    • http://ytovietnam.net/ckfinder/userfiles/files/najom.pdfIn PDF document text
    • https://relleno-acidohialuronico.com/wp-content/plugins/super-forms/uploads/php/files/0f9a8764f4d1022aeeeddec252ed1228/defimimijuge.pdfIn PDF document text
    • https://beauty-full.ru/uploads/files/purozonoredi.pdfIn PDF document text
    • http://alfatreyd-mebel.ru/archive/images/file/jiramalef.pdfIn PDF document text
    • https://telorgabus.com/contents/files/jazogazijabakezub.pdfIn PDF document text
    • http://miet-boot.ch/images/uploadedimages/file/84462288743.pdfIn PDF document text
    • http://cesarrodarte.com/userfiles/file/wobifobonarokus.pdfIn PDF document text
    • https://dom4m.de/userfiles/files/kibifiwiwol.pdfIn PDF document text
    • http://langyupharm.com/upload/files/75882718448.pdfIn PDF document text
    • http://xinyuemu.net/assets/202109/files/20210902183305643279.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/GLLx1DTH0VQ/uplcv?utm_term=free+robux+spinnerPDF 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_off0000d924.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD924 17744 bytes
SHA-256: 5aa988b5f7e8f004d0844771852066c82188c09572319707ff8c560cb886b651
font_01_sfnt_off00010768.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10768 10256 bytes
SHA-256: 002752877b5a2f2aba68fd4748f607db0941d07c3791827de872cb6b330baeca
font_02_sfnt_off00011e53.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E53 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1