Malicious PDF — malware analysis report

Static analysis result for SHA-256 727e81892b6b97d5…

MALICIOUS

PDF

80.4 KB Created: 2021-09-10 12:29:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: cbb4c53eab057b1a9ea53320717246d6 SHA-1: 5f8c8919bf062c2e9d82f25c31d7c1d03b0c5d4c SHA-256: 727e81892b6b97d5ab7fb882872bb02b58173a6c1dfe023cf3c0d242c19eba1d
156 Risk Score

Malware Insights

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

The file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. Static analysis revealed it functions as a link farm, with numerous URLs pointing to potentially compromised websites or disposable hosting. The presence of multiple PDF link farm heuristics and external URI firings supports this attack pattern. No scripts were extracted, limiting further analysis of specific payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9949

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://henghuitong.com/jingkelun/userfiles/files/20210903131012.pdf In PDF document text
    • http://www.rec39.ru/wp-content/plugins/super-forms/uploads/php/files/edc7664efd1b422caa0bcb759b61069e/bokugatosonabavazalup.pdfIn PDF document text
    • http://www.udelimpa.es/ckfinder/userfiles/files/modozezepupateminupi.pdfIn PDF document text
    • http://turskazka.ru/ckfinder/userfiles/files/99438935124.pdfIn PDF document text
    • http://bnblspecialities.com/userfiles/files/83784999605.pdfIn PDF document text
    • https://fokusmedia.com/images/uploads/51638878748.pdfIn PDF document text
    • https://bohemiamaestro.com/webpagebuilder/ckfinder/userfiles/files/55351605571.pdfIn PDF document text
    • http://www.next-conseil.fr/wp-content/plugins/formcraft/file-upload/server/content/files/161303bff78f06---zamatemupamepuxigosabo.pdfIn PDF document text
    • https://ladangmimpi2.com/contents/files/85238932729.pdfIn PDF document text
    • http://amandamaitland.com/images/file/fotobixanugip.pdfIn PDF document text
    • https://movie2book.com/userfiles/file/muzamejenuzefavizavedi.pdfIn PDF document text
    • https://holyfamilyhospitals.com/ckfinder/userfiles/files/logufefan.pdfIn PDF document text
    • http://eyela.kr/uploadfile/fckeditor/file/varedisabaseripeluvug.pdfIn PDF document text
    • http://jongauger.com/userfiles/file/70075116789.pdfIn PDF document text
    • http://geobigoni.it/userfiles/files/76139883413.pdfIn PDF document text
    • http://ifap.it/images/file/zavabegogewibesesubeteda.pdfIn PDF document text
    • http://rfinshaat.az/userfiles/file/suxesoduvonawimasiwalu.pdfIn PDF document text
    • https://floresdeserrezuela.com/aym_image/files/77664721001.pdfIn PDF document text
    • https://menu2uplus.com/images/file/pekevowabelafok.pdfIn PDF document text
    • https://miltonmattox.com/userfiles/file/99131506338.pdfIn PDF document text
    • https://mimpisiluman.com/contents/files/kanimifebakedalox.pdfIn PDF document text
    • http://flapboxes.custompackageboxes.com/userfiles/files/govax.pdfIn PDF document text
    • https://photographerin.agency/wp-content/plugins/super-forms/uploads/php/files/h984m7adf2393ku1a953cuppu3/35617712332.pdfIn PDF document text
    • http://decoworld.in/dayafter/uploadimages/newsimages/file/1421802202.pdfIn PDF document text
    • http://caythuocnam.org/images/files/ganexalamizumafozoruru.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/A3Ryygt5BCM/uplcv?utm_term=basic+wing+chun+training+pdfPDF 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_off0000da3e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA3E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f255.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF255 10840 bytes
SHA-256: 3262fb50b61a25629ac7e1a91a7bca44b513c7455426737adf7697ce006f0973
font_02_sfnt_off00010b2f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10B2F 15976 bytes
SHA-256: 543ba435a705a3df0d906a97aa8ff90e34a1d4c8c53e35ce7d5eb23f2c7f5655