Malicious PDF — malware analysis report

Static analysis result for SHA-256 8b43820f8bfcaa9a…

MALICIOUS

PDF

72.8 KB Created: 2021-09-07 23:04:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 64c331d0e47052e5dc9387b732a8f880 SHA-1: 5bbc7d841912f6511e7ca689d58f98dfa4b84e38 SHA-256: 8b43820f8bfcaa9a6463d4a9315eb3b3ed6acf51aa0a472781dcc3c497da6476
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous external URLs, many pointing to compromised CMS uploads or disposable hosting, suggesting a link farm or phishing lure. The presence of PDF-specific heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' further supports this, indicating the PDF's primary function is to redirect users to potentially harmful external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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://pistant.ru/uplcv?utm_term=spanish+greetings+worksheets+for+beginners PDF link annotation
    • https://www.hit-education.com/wp-content/plugins/super-forms/uploads/php/files/ndenmboke0t868rd5vmfc46ph6/63909216823.pdfIn PDF document text
    • https://hitourkorea.com/FileData/ckfinder/files/20210615_8809823AE3C7B458.pdfIn PDF document text
    • https://slide-bearing.com/d/files/30137066882.pdfIn PDF document text
    • https://aquafilling.com/userfiles/file/13230318736.pdfIn PDF document text
    • http://suachuaspa.com/upload/images-content/files/15046057348.pdfIn PDF document text
    • https://www.novet.de/wp-content/plugins/formcraft/file-upload/server/content/files/1606efa9021f04---zexofujepulosevizefeteso.pdfIn PDF document text
    • https://raiporjai.com/piceditor/file/17275143666.pdfIn PDF document text
    • http://jrpst.pl/userfiles/file/donofixinagorevupezoben.pdfIn PDF document text
    • https://militarynetwork.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160874695cc1a6---toreluj.pdfIn PDF document text
    • http://www.sg-callenberg.de/wp-content/plugins/formcraft/file-upload/server/content/files/160b49bc393cbd---21761748915.pdfIn PDF document text
    • http://pamatudarbai.lt/ckfinder/userfiles/files/82763604008.pdfIn PDF document text
    • http://europeanprofservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/16079f1b3da1b1---98085351067.pdfIn PDF document text
    • https://rachelrom.com/rescontent/file/rifudixikomemobonan.pdfIn PDF document text
    • http://maszyny.pl/userfiles/file/luvuwalevawabagilivu.pdfIn PDF document text
    • http://www.dogwoodagility.nl/ckfinder/userfiles/files/31546122653.pdfIn PDF document text
    • https://ou-ravda.com/ckfinder/userfiles/files/guporug.pdfIn PDF document text
    • https://k9-warrior.com/wp-content/plugins/super-forms/uploads/php/files/1465dqj7e68pidp5l5fm6ndb1i/20158543606.pdfIn PDF document text
    • http://futsalcb.cz/picture/vtextu/file/71976581442.pdfIn PDF document text
    • http://kortennis.co.kr/B/ck/ckfinder/userfiles/files/93088357997.pdfIn PDF document text
    • http://studiogiovannone.com/userfiles/files/87142035222.pdfIn PDF document text
    • https://ahi.com.ua/wp-content/plugins/super-forms/uploads/php/files/ce3a15f870a5e4aedb6e97bd58ce393e/40446442220.pdfIn PDF document text
    • http://claudiodauelsberg.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16085a83b036ee---57219873090.pdfIn PDF document text
    • http://mirembeestate.co.ug/wp-content/plugins/formcraft/file-upload/server/content/files/1608d2aa5c528b---fawukuxudolokukefoj.pdfIn PDF document text
    • 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_off0000b99d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB99D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d1af.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD1AF 16524 bytes
SHA-256: b8881ec1f22a8cddeae723c851e58c632a3741ed1b845e48267351f9029f9cc4
font_02_sfnt_off0000fc11.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC11 10984 bytes
SHA-256: 4c335a6db82ad0f04423d6524dc9febce5c1ed6a5d874c1a31f9507a8908af0e

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