Malicious PDF — malware analysis report

Static analysis result for SHA-256 400288cc4d958db9…

MALICIOUS

PDF

83.1 KB Created: 2021-09-20 02:32:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 8966493907daef100d11aa2d3b4f05f7 SHA-1: 19078ab4d7f60c652b66326adf3ebdb6d3dbb6c3 SHA-256: 400288cc4d958db9238dadf0505e63c9314ee910c66f55bc064e146bf3f9d591
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external links, many pointing to compromised WordPress uploads and disposable hosting, indicating a link farm designed to redirect users to malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware delivery. No scripts were extracted, but the PDF structure itself facilitates the attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 7

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://synerhu.ru/uplcv?utm_term=the+infinite+atonement+pdf+free
    • http://slmj8.com/data/userfiles/files/tijapabapemulusemixumex.pdf
    • https://sevenhillsgroup.net/ckfinder/userfiles/files/rokigudixenuvotabu.pdf
    • https://tidurmalam2.com/contents/files/lisegesokutiledes.pdf
    • http://kdsonline.org/userfiles/file/lulokavinivilelefozeka.pdf
    • http://nghiencuuykhoa.com/uploads/userfiles/file/tivabadenoxitibisaridepul.pdf
    • http://protectakoteasia.com/ckfinder/userfiles/files/lugafadojopabovewafigakur.pdf
    • https://maribon.net/app/webroot/files/userfiles/files/jolixesokomelokitipixo.pdf
    • https://internationallanguagenavigators.com/media/68916127193.pdf
    • http://yeongwonenc.com/userfiles/file/xagiropatake.pdf
    • http://tarnava.eu/user_images/file/viwadokire.pdf
    • https://maxflowfans.com/userfiles/file/tufirusopoto.pdf
    • http://karaokejdi.com/ckfinder/core/connector/php/upload/files/derenimuxenuwotetivewi.pdf
    • http://dermalab.pl/userfiles/file/turulago.pdf
    • https://flyags.com/editorResources/file///18299804652.pdf
    • https://ewms.vn/wp-content/plugins/super-forms/uploads/php/files/926l9ujdsb9m52ralbh053p58n/75810518525.pdf
    • https://777mto.info/contents/files/tetafefutaluropajiwagodu.pdf
    • http://epwuae.com/userfiles/file/13353157362.pdf
    • https://xn--80adj7cxa.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/9b7c969b3497feaa42e46e661d3122b9/76437856993.pdf
    • http://www.scea.edu.mn/ckfinder/userfiles/files/65187343412.pdf
    • http://sklepjola.pl/userfiles/file/55386716382.pdf
    • http://we2meeting.com/ckfinder/userfiles/publics/files/22784946687.pdf
    • http://www.rebranded.tv/wp-content/plugins/formcraft/file-upload/server/content/files/16139d1a15cb9d---buvojivawomovabilerabepur.pdf
    • https://autoskola-scp.com/files/buwex.pdf
    • 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_off0000e0b4.bin
b48639e9fabbf581012d355ddfc7d14446d07a3a1e297a6ad162dfc0af6f8800
pdf-font-stream PDF embedded font (sfnt) at offset 0xE0B4 18184 bytes
font_01_sfnt_off00010ef8.bin
ad871175b88339eb96841f631200266265dae9e990ca8c172118864853b922fe
pdf-font-stream PDF embedded font (sfnt) at offset 0x10EF8 10512 bytes
font_02_sfnt_off000126a9.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x126A9 16792 bytes