Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4134b7877c3eb6f…

MALICIOUS

PDF

81.0 KB Created: 2021-09-21 08:50:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 15e793e3272962533bca61b70602223c SHA-1: 59cc2e30bf0f5d123f9f0c1c480eb11e2a8fd8b9 SHA-256: b4134b7877c3eb6fb772d57db4642bd5bd81678bd7892be6964408675757b2e1
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate the document contains a link farm pointing to compromised CMS upload storage and disposable hosting, likely to disguise malicious URLs. The presence of embedded URLs and the nature of the heuristics suggest the document is designed to redirect users to external sites, potentially for phishing or to download further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

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://newcityhk.com/userfiles/rugatem.pdf
    • http://feynburg-uhren.de/uploads/kutariniwo.pdf
    • https://sv-fin.ru/wp-content/plugins/super-forms/uploads/php/files/844fdfae687fd24ed5585dcc2dcc9736/56697419584.pdf
    • http://ebbers-schilderwerken.nl/uploads/files/19602075731.pdf
    • https://mercedesmazo.es/wp-content/plugins/formcraft/file-upload/server/content/files/1613880868c4f7---kafabimali.pdf
    • http://tobn56.com/UpFiles/file/62804710363.pdf
    • https://protrialse.eu/files/files/kipizivamupap.pdf
    • http://www.extramas.com/userfiles/files/97982151631.pdf
    • https://xn--80adj7cxa.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/64910b5941119ac7933cefa08770141a/popizizibojunumu.pdf
    • http://ytbozhuo.com/upload/file/141728439329.pdf
    • http://gzcil.com/uploadfile/files/nijetijedivirezo.pdf
    • http://donghobaoan.com/uploads/files/zokuvibuwinabapiluti.pdf
    • https://bocion.com/ckfinder/userfiles/files/76142153604.pdf
    • https://www.beewellrx.com/wp-content/plugins/super-forms/uploads/php/files/tmp/lowaw.pdf
    • http://es-manzokudou.com/yamituki-n/uploads/files/punadiwijelurabivexu.pdf
    • http://abwingssuffolk2.com/uploads/files/gijijiwaziwexifigeson.pdf
    • https://yourtuscanyguide.com/wp-content/plugins/super-forms/uploads/php/files/6v5mu4r9tdmsubsnu88nspp9t4/wogirodubokupefezazoju.pdf
    • https://jagamimpi.info/contents/files/31660275369.pdf
    • http://studiotecnicobergamaschi.it/userfiles/files/12859204577.pdf
    • https://www.grecosalesinternational.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614082c7da9fc---sutadofagolikimimuvatu.pdf
    • http://jsdarvin.com/files/xomezabup.pdf
    • https://divorcioconsensual.com.br/wp-content/plugins/super-forms/uploads/php/files/97c74c89aba58ad2ab87e66efaec516e/18163335537.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/FevRqgeaUVY/uplcv?utm_term=pdf+to+excel+online+converter+free+online
    • 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_off0000d954.bin
b8efdae90d73c413b92edee97078f8335b333f69459541509ce43a984591a2bc
pdf-font-stream PDF embedded font (sfnt) at offset 0xD954 10308 bytes
font_01_sfnt_off0000f0a6.bin
47e9d1a9b1a0b4874ff202a2b6f9bebb7494b682c7731f8e9ca7824491532fe5
pdf-font-stream PDF embedded font (sfnt) at offset 0xF0A6 17256 bytes
font_02_sfnt_off00011dc7.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x11DC7 16792 bytes