PDF malware analysis — malicious · c1630495e61b57c8

MALICIOUS

PDF

71.0 KB Created: 2021-09-19 06:48:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27

MD5: 3d784605fb40cc1a202e49030a79bab2 SHA-1: 719a5237f4291f469b61e1317db3b188f578758e SHA-256: c1630495e61b57c82c0c92f8b41f6fec9317f347cf6d11e2face1569d3787597

156 Risk Score

Malware Insights

MITRE ATT&CK

T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with many embedded URLs pointing to various websites, including those hosted on compromised CMS uploads. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

Machine Learning

Nyx PDF Classifier malicious score 0.9993

Heuristics 6

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.
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 https://huntic.ru/uplcv?utm_term=the+binding+of+isaac+rebirth+unblocked PDF link annotation
- https://burstallconrad.com/editor_files/file/gagewupes.pdfIn PDF document text
- http://tuttotop.com/userfiles/files/48507550681.pdfIn PDF document text
- http://hellnocancershow.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613dcc1f64cc3---kaziwedijelaliwi.pdfIn PDF document text
- http://tekizolasyon.com/ckfinder/userfiles/files/ketibuf.pdfIn PDF document text
- http://reylab.com/userfiles/file/mezunaf.pdfIn PDF document text
- http://hferrynetworks.com/FileData/ckfinder/files/20210907_DB726725A7C2B287.pdfIn PDF document text
- https://www.uniqueartzz.com/wp-content/plugins/super-forms/uploads/php/files/2ehm81o9gfhsa49do3861fr0ml/sekuzefebekopefonulipazo.pdfIn PDF document text
- http://xn--rssx31a7tec6p.com/upload/userfiles/files/20210911224741.pdfIn PDF document text
- https://bibliotheque-des-arts.ch/ckfinder/userfiles/files/zeweruzuj.pdfIn PDF document text
- http://www.brennholz-heinlein.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613c20898a687---mawegivovoxenaludepusiwof.pdfIn PDF document text
- http://studiogiamberardino.it/userfiles/files/pamovativimazofeluliruwu.pdfIn PDF document text
- http://www.gainerwindows.ca/wp-content/plugins/super-forms/uploads/php/files/9rn9uhkjm3idt7khgg9bc2n3r7/35755977942.pdfIn PDF document text
- https://inoxquochoang.com/app/webroot/files/images/pages/files/xazinowatoforuvaleguruzoz.pdfIn PDF document text
- https://citronixdeflection.com/nbloom/fckuploads/file/91051997392.pdfIn PDF document text
- http://another-partner.morefriendship.com/upload/files/88171474949.pdfIn PDF document text
- https://christianboudreau.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613d78f2aeb42---sipinagefezogotemevadake.pdfIn PDF document text
- http://premo.at/userfiles/file/fulukebededaper.pdfIn PDF document text
- 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_off0000b1a1.bin`	pdf-font-stream	PDF embedded font (sfnt) at offset 0xB1A1	16876 bytes
SHA-256: `715284ca7cbb553003fd515c73db18d77f83f4ff9e1dc8136b8cd797bfce70b4`
`font_01_sfnt_off0000dd3c.bin`	pdf-font-stream	PDF embedded font (sfnt) at offset 0xDD3C	16792 bytes
SHA-256: `9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1`
`font_02_sfnt_off0000f553.bin`	pdf-font-stream	PDF embedded font (sfnt) at offset 0xF553	11052 bytes
SHA-256: `bff0cafdc7d3824c76d904d3900341dcceb5674976e4a2e8dd74594c5f55680c`

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