Malicious PDF — malware analysis report

Static analysis result for SHA-256 4983d86896334510…

MALICIOUS

PDF

87.2 KB Created: 2021-09-19 10:30:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 50a981ae6231194ec23c011fb9245839 SHA-1: 841768102bd960d62a09b8d4bcde8ff3756a287e SHA-256: 4983d86896334510db8c7c4c2e604fcb6abb5e1e857b7a96a19ff3654c3bdcff
176 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple potentially compromised or disposable hosting sites. The presence of numerous embedded URLs, many pointing to user-uploaded content directories on various domains, strongly suggests a phishing or SEO poisoning campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9961

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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.
  • QR-code redirect lure medium SE_QR_LURE
    Document instructs the user to scan a QR code with a phone — consistent with QR phishing, but also common in legitimate documents
  • 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://barexkft.hu/userfiles/file/33292356375.pdf
    • http://essentielles-theater.de/UserFiles/File/rusudokiriruj.pdf
    • https://artcorner-fiberglass.com/userfiles/files/79587202427.pdf
    • http://krasneclanky.cz/uploads/33988045173.pdf
    • https://shellserva.nl/docs/Image/file/54966745217.pdf
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137583cc1a04---37244115346.pdf
    • http://greenflameenergy.com/userfiles/file/95629275631.pdf
    • http://colorfusion.us/admin/images/file/jadinunozuviwizububebo.pdf
    • https://intersensor.ro/v2011/Files/fck_upload/file/73163479087.pdf
    • http://tractortools.cz/ckfinder/userfiles/files/pajawokalonenixezemuje.pdf
    • https://botroul.be/uploads/36875477961.pdf
    • http://twtime.com/uploads/files/202109030356082173.pdf
    • https://www.landalastadservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/16131d695295cd---68627371053.pdf
    • http://dmn.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16138f6f8022ae---sosudogozimotubam.pdf
    • http://tabletopad.com/images/file/70402079711.pdf
    • http://zzzwchem.com/upload/files/visiniv.pdf
    • http://psystems.gr/Administrator/uploads/userpics/OutPostImages/files/xagasazokejune.pdf
    • https://godparents4tz.org/home/god/public_html/ckfinder/userfiles/files/wuzegajujixoden.pdf
    • https://tselectromechanical.com/uploads/CKfiles/files/75367516241.pdf
    • http://jtravel.clickis.kr/FileData/ckfinder/files/20210902_DBDB9C2A4D6B7CAC.pdf
    • http://nicenpos.com/userData/board/file/17600504412.pdf
    • https://nieruchomosciturystyczne.eu/files/file/zomazezovuzorevu.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3CAf4wW3hvY/uplcv?utm_term=things+to+do+in+the+nether+minecraft
    • 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_off0000f09e.bin
763dc65c104be9fd8be3293edbdaed266131a581792520b3f1191e440431f110
pdf-font-stream PDF embedded font (sfnt) at offset 0xF09E 17632 bytes
font_01_sfnt_off00011eb0.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x11EB0 16792 bytes
font_02_sfnt_off000136c7.bin
754df7cbda1dd197c33a33882185d3d411e989cebf28b2fe5c39dbe732b2eb5a
pdf-font-stream PDF embedded font (sfnt) at offset 0x136C7 10840 bytes