Malicious PDF — malware analysis report

Static analysis result for SHA-256 4fef04c058d4d2e1…

MALICIOUS

PDF

84.7 KB Created: 2021-10-12 07:01:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 945e0c656a2cded9b0e7c50210ec20b3 SHA-1: 02506c0c152b70bec77f732a2389f726984d9506 SHA-256: 4fef04c058d4d2e1af570db42377245f79d443e63fb377e6eb73ad3cb7fa8d66
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file was identified as malicious by an ML classifier and contains numerous embedded URLs. Several of these URLs point to compromised WordPress upload directories or are part of link farms hosted on disposable domains, indicating a potential distribution mechanism for malicious content. The document body is heavily obfuscated and unreadable, providing no direct clues to its specific purpose beyond the link farm heuristic.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9961

Heuristics 5

  • 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://studiotecnicodambra.eu/userfiles/files/13744527452.pdf In PDF document text
    • https://sirikulsteel.com/wp-content/plugins/formcraft/file-upload/server/content/files/161416cbf7f384---mivinetukimujupazajew.pdfIn PDF document text
    • http://autosklo.sk/pictures/file/38783546850.pdfIn PDF document text
    • http://okna-dvere-online.cz/media/upload/upload/file/50342255554.pdfIn PDF document text
    • https://greenlakecruises.com/ckfinder/userfiles/files/606097397.pdfIn PDF document text
    • https://askisan.com/upload/ckfinder/files/22501157803.pdfIn PDF document text
    • http://12shio2.com/contents/files/84866949094.pdfIn PDF document text
    • http://chineseclothingonline.net/File/33256617804.pdfIn PDF document text
    • http://stavclearing.ru/upload/files/92488260982.pdfIn PDF document text
    • https://masterok-kovka.ru/wp-content/plugins/super-forms/uploads/php/files/69b92e1e77d02e0bfaae615eb06aa472/89266933420.pdfIn PDF document text
    • http://wahluenfty.com/userfiles/27038892929.pdfIn PDF document text
    • https://exlite.it/ckfinder/userfiles/files/13168973065.pdfIn PDF document text
    • https://cissud.it/uploads/ck_editor/files/20346351926.pdfIn PDF document text
    • https://speculatio.in/ci/userfiles/files/16116599257.pdfIn PDF document text
    • https://h1t-urlaurora1-turbo.com/contents/files/dedupevazesibufor.pdfIn PDF document text
    • https://creationstationdance.com/wp-content/plugins/formcraft/file-upload/server/content/files/1615ad91ad14fc---vopijesozekoliloloturo.pdfIn PDF document text
    • http://huyndaicaudien.com/upload/files/58580837607.pdfIn PDF document text
    • https://eksiliotomotiv.com/upload/ckfinder/files/suvat.pdfIn PDF document text
    • https://rtquery.reitoken.org/Coaching123/images/files/nimapareduviguvebuwebosad.pdfIn PDF document text
    • http://freestyler.cz/img/file/jegawovimitaxuk.pdfIn PDF document text
    • https://augsburger-dartliga.de/uploads/file/diwizelokuja.pdfIn PDF document text
    • https://electroagro.es/pub/files/lokokoxug.pdfIn PDF document text
    • http://feedproxy.google.com/~r/Xvkpad/~3/xPAns0MRe5M/uplcv?utm_term=old+poster+texturePDF 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_off0000e4e3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4E3 19140 bytes
SHA-256: 8d1a35bc5068766d6c6a75e06dcb17474e4f13e1fdf237fd3a995ba7d68f499b
font_01_sfnt_off00011636.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11636 10252 bytes
SHA-256: 658ea1027f2eb463e6fb9eb72c0e16a8d26fa04c7f953d196d9c98ac706929c4
font_02_sfnt_off00012d6e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12D6E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1