Malicious PDF — malware analysis report

Static analysis result for SHA-256 a853a595874d2a0c…

MALICIOUS

PDF

85.8 KB Created: 2021-09-19 20:51:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 04d66e698db9af338dab353b99395f19 SHA-1: b73173303cfada9f1a24c02c3d4e41efbbe30325 SHA-256: a853a595874d2a0c78226939d1ee856e58d2af232fa0917e105cc4410f26f3cc
156 Risk Score

Malware Insights

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

The PDF contains numerous external links, many pointing to compromised WordPress sites or disposable hosting, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware delivery. The presence of multiple PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics further supports this, as does the PDF_URI pointing to a URL with 'apk installer' in the UTM term, suggesting a lure for potentially unwanted software.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://synerhu.ru/uplcv?utm_term=apk+installer+for+windows+7 PDF link annotation
    • http://ct-tci.com/cttax/userfiles/files/89049970821.pdfIn PDF document text
    • http://topp.pl/_topp/file/88833157048.pdfIn PDF document text
    • http://siddharpeedam.org/userfiles/file/In PDF document text
    • http://dtyxbpzx.com/filespath/files/20210902040245.pdfIn PDF document text
    • https://www.vpn-solutions.com.pe/ckfinder/userfiles/files/tupozajevemodogixa.pdfIn PDF document text
    • http://www.louisefarmersmith.com/admin/ckeditor/ckfinder/userfiles/files/6471623319.pdfIn PDF document text
    • https://xn--90aweabvm.xn--p1ai/ckfinder/userfiles/files/13479112017.pdfIn PDF document text
    • https://www.advids.co/wp-content/plugins/formcraft/file-upload/server/content/files/161312d9412410---98573793540.pdfIn PDF document text
    • http://lnianemarzenie.pl/userfiles/file/26845226245.pdfIn PDF document text
    • https://www.hdontheroadnapoli.it/wp-content/plugins/formcraft/file-upload/server/content/files/16139e6077eb87---tepogabi.pdfIn PDF document text
    • http://isystemlab.com/admin/ckfinder/userfiles/files/63649379809.pdfIn PDF document text
    • http://nhatrangpalace.net/app/webroot/upload/files/vonunup.pdfIn PDF document text
    • http://dakov.hu/_user/file/majijol.pdfIn PDF document text
    • http://naturallabs.fr/userfiles/file/25335108096.pdfIn PDF document text
    • http://lyzjkgm.com/d/files/31532494257.pdfIn PDF document text
    • https://ladida.asia/sporlegen/administrator/imagetempfile/20447896807.pdfIn PDF document text
    • http://paymentsbusiness.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1613745d5e1b8c---luzuriva.pdfIn PDF document text
    • http://www.pataniforum.com/admin/jquery/ckfinder/userfiles/files/61428412302.pdfIn PDF document text
    • http://staresecurity.com/userfiles/file/5253410824.pdfIn PDF document text
    • https://marksiegeldds.com/wp-content/plugins/super-forms/uploads/php/files/5e263a6d47831892abb148e47e298727/xilikovibuloxixigerimefef.pdfIn PDF document text
    • http://vivaibonomo.it/userfiles/files/80288807790.pdfIn PDF document text
    • http://deborahkay.com/ckfinder/userfiles/files/25322855568.pdfIn PDF document text
    • http://aelma.com/sites/default/userfiles/file/wigigivagerodatekoj.pdfIn PDF document text
    • http://e-pisanie-prac.pl/famprojekt_z_serwera/images/file/xikosederanavasevifaj.pdfIn PDF document text
    • http://bjerkelunden.org/content/files/userfiles/file///wupenakanopoposisoruzata.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.

FilenameKindSourceSize
font_00_sfnt_off0000e8c4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE8C4 18384 bytes
SHA-256: 8119dd658bd8d2ba8c9b927386d0da7d6197696603bf34f049bb893c2c613b6b
font_01_sfnt_off000118b1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x118B1 10700 bytes
SHA-256: f1f3c3072181b88307e32ba92a7dbb03cec7108362aca9cdbebabe3021f3c4f4
font_02_sfnt_off00013191.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13191 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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