Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4b935539973e48d…

MALICIOUS

PDF

78.7 KB Created: 2021-09-23 15:18:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 99e0a60f531e1aa94aca1eaf035433c7 SHA-1: 6c7eeb7fbf648a0c999255c412a80d4d688840ed SHA-256: b4b935539973e48d17e37a9d193d3add1a3fe8fc744bed9f8d2353870f85d70d
156 Risk Score

Malware Insights

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

The sample is identified as a malicious PDF by multiple heuristics and a machine learning classifier. It contains numerous external URIs and links to potentially compromised websites, indicating a phishing or malware distribution attempt. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics suggests the PDF is part of a link farm designed to improve search engine ranking for malicious sites or to host malicious content on compromised infrastructure. No scripts were extracted from this sample.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9958

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 https://crysiq.ru/uplcv?utm_term=microwear+w26+plus+price+in+bangladesh
    • http://techmechengineers.com/uploads/xojitazopinimotaw.pdf
    • http://www.galiantsolutions.com/emailimages/file/vovoluwulidujogu.pdf
    • http://thanhnhomdinhhinh.net/uploads/files/44388303393.pdf
    • https://giverny-bkk.com/upload/files/44412680636.pdf
    • https://brianhigbielaw.com/UserFiles/file/14332058231.pdf
    • https://goodline.by/userfiles/file/34658263973.pdf
    • http://euredit-editions.com/userfiles/file/faragezalul.pdf
    • https://fgcrubochi.com.ng/ckfinder/userfiles/files/80995061566.pdf
    • https://tunhuaduytan.com/upload/userfiles/files/17799407550.pdf
    • https://t-groupvnxkld.com/uploads/news_file/7663511647.pdf
    • http://nexxosrealty.com/userfiles/files/mopofajexudeke.pdf
    • http://thetsaban3watnuea.com/UserFiles/file/depiguzupuvisupegufezedi.pdf
    • http://ilkjv.com/Images/Media/files/45633158868.pdf
    • https://pass-eco-energies.com/ckfinder/userfiles/files/1993993571.pdf
    • https://kaktutzhit.by/uploads/files/6592328805.pdf
    • https://horgaszvelem.elelmiszer-hazhozszallitas.hu/ckfinder/userfiles/files/silokazumidelapedoridatas.pdf
    • https://vizzzio.ru/wp-content/plugins/super-forms/uploads/php/files/4fa118927e85f87de39501276ea3adc2/sumudilada.pdf
    • http://studiotecnicoarduini.eu/userfiles/files/sozarebigaxad.pdf
    • https://celovechurch.org/wp-content/plugins/super-forms/uploads/php/files/5cdea8a319b0c685a856f3ff5f9b6d4f/tusunajazumadonit.pdf
    • http://www.expertnutritionadvisor.com/wp-content/plugins/formcraft/file-upload/server/content/files/16143cb2b4d8a7---8794312567.pdf
    • http://sattosushi.com/uploads/files/52504693759.pdf
    • https://chrmglobal.com/userfiles/file/vabomopidodal.pdf
    • http://www.benvenutialmare.com/wp-content/plugins/formcraft/file-upload/server/content/files/161428a882c230---54435756067.pdf
    • 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_off0000c8ce.bin
f049bcc874cd5921cd387c0da3143f38751647a281036498bade653068742c4f
pdf-font-stream PDF embedded font (sfnt) at offset 0xC8CE 11300 bytes
font_01_sfnt_off0000e2f3.bin
9b7d83f8261a179673cbd88ab523f9d10d6e06135f715f1e16218292bbe0dfa0
pdf-font-stream PDF embedded font (sfnt) at offset 0xE2F3 19212 bytes
font_02_sfnt_off00011546.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x11546 16792 bytes