PDF malware analysis — malicious · ef073d50d21129e1

MALICIOUS

PDF

75.0 KB Created: 2021-07-27 16:44:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-27

MD5: ce452692a90d258b79ad7b088989b227 SHA-1: eb0596e523a08373a328ed8af144c41bfc0f3db7 SHA-256: ef073d50d21129e1c34d0d7d65cbef9211a219e07596317142c2fb11b85cf5b0

156 Risk Score

Malware Insights

MITRE ATT&CK

T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous URLs pointing to compromised WordPress sites and other domains, likely intended to lure users to malicious content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not meant for direct user interaction but rather as a container for malicious links.

Machine Learning

Nyx PDF Classifier malicious score 0.9993

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://grupomarsamo.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e8e765dca59---xedubosinuxakowamefopevi.pdf In PDF document text
- http://balogmihaly.hu/UserFiles/file/850812707.pdfIn PDF document text
- http://saamfactory.com/wp-content/plugins/super-forms/uploads/php/files/29f703971fdc3c9cdef575be44040689/95760136635.pdfIn PDF document text
- https://wkd-uk.com/wp-content/plugins/super-forms/uploads/php/files/754a678a6c0d64b29a3e7e457d7c0daf/didulilipufezexunolu.pdfIn PDF document text
- https://bajrahrs.com/userfiles/file/moxijufafavugifa.pdfIn PDF document text
- http://trackeg.com/en/wp-content/plugins/formcraft/file-upload/server/content/files/1609fea55cfee2---xidimozebelu.pdfIn PDF document text
- https://saftanton.dk/wp-content/plugins/formcraft/file-upload/server/content/files/16098a280925d5---37275976133.pdfIn PDF document text
- http://jagatjyotischool.org/jagatjyotischool/userfiles/file/vesogufapuxatisiw.pdfIn PDF document text
- https://uzmanwebci.com/calisma2/files/uploads/53806649506.pdfIn PDF document text
- https://www.finestkindcharter.com/wp-content/plugins/formcraft/file-upload/server/content/files/160725ad045068---norupotorimisub.pdfIn PDF document text
- http://ski-experience-japan.com/images/blog//file/34844989002.pdfIn PDF document text
- http://mko-yug.ru/wp-content/plugins/super-forms/uploads/php/files/59829f2cb21e3cdbf395b853aa872267/womufivojofi.pdfIn PDF document text
- http://www.sunarmisir.com.tr/wp-content/plugins/super-forms/uploads/php/files/58paqa9ff4643iefahg4svnn50/41289160409.pdfIn PDF document text
- https://puertoestereo.com/wp-content/plugins/super-forms/uploads/php/files/np9u7scm6qhpbl91fe4dr0p76i/5479417360.pdfIn PDF document text
- https://ontime-taxi.kg/wp-content/plugins/super-forms/uploads/php/files/e49f84c132e492c33bd2d708a917db1e/62281246858.pdfIn PDF document text
- http://posicert.com/upload_fck/file/2021-7-27/20210727190831715863.pdfIn PDF document text
- http://soflocops.net/clients/81266/File/zepefotivata.pdfIn PDF document text
- https://www.rekalibracija.com/wp-content/plugins/super-forms/uploads/php/files/d823efbcdd6c847da2009394fa19ba94/66505654614.pdfIn PDF document text
- https://afriqueitnews.com/wp-content/plugins/super-forms/uploads/php/files/6f4ade96a82ccd89716ffec48d0133a7/41021047103.pdfIn PDF document text
- http://xiaohecollege.com/d/files/76587890644.pdfIn PDF document text
- http://atthaya.com/file_media/file_image/file/wajesumikurunujixal.pdfIn PDF document text
- http://www.grupohk.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160b761c51ee42---vetazerujenitup.pdfIn PDF document text
- https://beaufortbond.com/wp-content/plugins/super-forms/uploads/php/files/80cefa529542b7675a805c03bc396e39/dekujazutisefuxuzitibibi.pdfIn PDF document text
- https://feedproxy.google.com/~r/Uplcv/~3/Om9ozkHLxGw/uplcv?utm_term=accounting+information+system+james+hall+10th+editionPDF 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.

Filename	Kind	Source	Size
`font_00_sfnt_off0000c06c.bin`	pdf-font-stream	PDF embedded font (sfnt) at offset 0xC06C	11420 bytes
SHA-256: `d710e93e99f67d9bb08470641e2c2daa2a5f1d17a549e531a5a4a47c44b9ba45`
`font_01_sfnt_off0000db15.bin`	pdf-font-stream	PDF embedded font (sfnt) at offset 0xDB15	16792 bytes
SHA-256: `9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1`
`font_02_sfnt_off0000f327.bin`	pdf-font-stream	PDF embedded font (sfnt) at offset 0xF327	16452 bytes
SHA-256: `a7f9f68058d0abb0bb82f7615de0db1be8d9110165543c747aae7321f97b7a11`

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