Malicious PDF — malware analysis report

Static analysis result for SHA-256 8553ac1b81689a2f…

MALICIOUS

PDF

72.0 KB Created: 2021-09-27 05:09:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: e9354698220f36ec87dba21bfdad65a8 SHA-1: 8e6314fc6c434a976d40ed1ccf90cc9c4ecc5746 SHA-256: 8553ac1b81689a2fd92243be85bbc6cd95d0b156131716fa82a7911b665b6a60
156 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics and a machine learning classifier as malicious, with ClamAV identifying it as a phishing trojan. It contains numerous links, many pointing to compromised CMS uploads or disposable hosting, suggesting a link farm designed to redirect users to malicious sites. The document body is heavily obfuscated and unreadable, providing no direct user-facing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9837

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://russkiivopros.com/images/FCKeditor/file/78021643752.pdf In PDF document text
    • https://makemycake.gr/wp-content/plugins/super-forms/uploads/php/files/1dq1q51k90ekruju5nh66cki9g/43524989304.pdfIn PDF document text
    • http://www.stallionreadymix.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/16145a6dc27957---67282740696.pdfIn PDF document text
    • https://belitour.ir/basefile/belitourir/files/66019104478.pdfIn PDF document text
    • http://villkasz.hu/editor_up/rexugipokaga.pdfIn PDF document text
    • http://zkojicin.cz/userfiles/file/vaxozi.pdfIn PDF document text
    • https://www.auto-ecole-acm.com/ckfinder/userfiles/files/7473104502.pdfIn PDF document text
    • http://theurbanbazzaar.com/userfiles/file/98364175497.pdfIn PDF document text
    • http://qataminational.com/uploaded_files/userfiles/files/giloxezuzomajesoga.pdfIn PDF document text
    • http://gzcil.com/uploadfile/files/wirefijipuvogupojoxota.pdfIn PDF document text
    • http://vektor28.ru/userfiles/file/7836433221.pdfIn PDF document text
    • http://dxczx.com/ckfinder/userfiles/files/20210926_224914.pdfIn PDF document text
    • https://jss-moms.si/upload/File/66436457159.pdfIn PDF document text
    • http://zadonskiy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16147aceb3ec8d---54218499177.pdfIn PDF document text
    • http://www.meglobalinc.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/16141cac7d4045---92583201915.pdfIn PDF document text
    • https://oykufestivali.com/ckfinder/userfiles/files/dotokuxizef.pdfIn PDF document text
    • https://kaptenhoki.org/contents/files/2904873426.pdfIn PDF document text
    • http://strelnicebudejovice.cz/userfiles/file/redaburufadopemerojowibe.pdfIn PDF document text
    • http://gruaszarate.com/ckfinder/userfiles/files/39470568477.pdfIn PDF document text
    • https://www.sevgiliyevideo.net/wp-content/plugins/formcraft/file-upload/server/content/files/1613fd02db3671---sozodurudufowadasere.pdfIn PDF document text
    • https://viettrungson.com/media/Files/54191127136.pdfIn PDF document text
    • https://bf-pomosch.ru/wp-content/plugins/super-forms/uploads/php/files/armq9c33mbfi5t13vq49d9lmg0/25527047574.pdfIn PDF document text
    • https://pasationtravellers.com/root/FCKeditor/file/49431410867.pdfIn PDF document text
    • http://grotech.in/userfiles/file/pazowatusisolusig.pdfIn PDF document text
    • http://squarcialupirelaxinchianti.com/writable/public/userfiles/file/90737084819.pdfIn PDF document text
    • https://wendi101.com/userfiles/file/75559704035.pdfIn PDF document text
    • http://www.protectakoteasia.com/ckfinder/userfiles/files/49659694457.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1xuhb7AK25c/uplcv?utm_term=turn+on+usb+storage+android+not+showingPDF 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_off0000b5ac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB5AC 17080 bytes
SHA-256: e7c923be6793132f769d8cde7fe1684e7f91f060758591d7d21a3dd175cb4583
font_01_sfnt_off0000e137.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE137 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f94e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF94E 10768 bytes
SHA-256: cde0807f19cfbc9a9948f9d823dce760e6a2dc7b3441bbeaa88fc4e30f6af911