Malicious PDF — malware analysis report

Static analysis result for SHA-256 85c51e87679bf64e…

MALICIOUS

PDF

87.7 KB Created: 2021-07-05 11:47:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 8eb054e00b4d52c87306765a997fed16 SHA-1: dac6b49ad14cb2cf1c868ce2135f3be37bd566b7 SHA-256: 85c51e87679bf64ecd60a72e2abf0b848b11a96db8fdd6edadddbe44ab9a705b
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ML classifiers and ClamAV, specifically as a phishing trojan. It contains numerous links pointing to compromised WordPress upload directories and other disposable hosting, suggesting a link farm designed to distribute malicious content. The presence of these links, particularly those with UTM parameters hinting at search engine optimization for software downloads, indicates an attempt to trick users into downloading malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

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://pcmcpropertyblog.com/wp-content/plugins/super-forms/uploads/php/files/aea6bfffa6a0250ac09faa0863965e25/58706106004.pdf
    • http://discarga.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aa3cbfc57df---8339941547.pdf
    • http://studiosiriosrl.it/userfiles/files/68326916770.pdf
    • http://waukeganeast1980.com/clients/877304/File/13930832718.pdf
    • http://feach.ie/images/uploads/file/pafoxutumewomad.pdf
    • https://la-klamm.org/userfiles/file/48882604513.pdf
    • http://abapaposentados.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16084b0f2bebb0---sidusut.pdf
    • https://lisacutler.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b76f8071619---92579119091.pdf
    • http://asustainable.com/global/file/romuwixurujuwemedobili.pdf
    • http://raunlarose.us/wp-content/plugins/formcraft/file-upload/server/content/files/16087e0ee7cd3b---zotoj.pdf
    • https://thriveelearning.com/wp-content/plugins/super-forms/uploads/php/files/ba30832918c4b8641c6c598235f2aa8b/runutofamakanasi.pdf
    • http://vaness-sens.fr/ckfinder/userfiles/files/61833725057.pdf
    • https://shared401k.com/wp-content/plugins/super-forms/uploads/php/files/dc1ca420ec4e8c666b288e5a78bc9658/99042949693.pdf
    • http://www.immiflex.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b5755beeb98---48907751419.pdf
    • https://ohcsi.com/ckfinder/userfiles/files/guzumilixagavuzubejokow.pdf
    • https://an-professional.ru/img/files/file/bilonewenomogenus.pdf
    • https://www.lipfish.no/wp-content/plugins/formcraft/file-upload/server/content/files/160a1ca3fdb596---60038989535.pdf
    • https://www.financedeclined.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1607eebf9effea---pajeworofowimokeda.pdf
    • http://hrt-foto.hu/_user/file/14521913049.pdf
    • https://luminex.pl/upload/file/wunikit.pdf
    • http://massageindex.nl/images/uploads/tipowarexamitujerunel.pdf
    • https://slavica.ru/wp-content/plugins/super-forms/uploads/php/files/b6f75dcbff865976fb8582fb8e31b9e5/34239224561.pdf
    • https://calmoinc.com/upload/editor/file/83206956402.pdf
    • https://northstarexecutivesearch.com/wp-content/plugins/super-forms/uploads/php/files/c462a761be6e84f22417f51501bf08a8/28732439951.pdf
    • https://whitelightdesign.com/wp-content/plugins/super-forms/uploads/php/files/5296f8613a413e5c58b91dbfd1617d63/87103506135.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/fzgW7-mxBc0/uplcv?utm_term=ms+office+2007+download+for+windows+10+64+bit
    • 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_off0000f05d.bin
9706c5662bef0916419142fdd39d0878b9fcd9e3af82471bc8b1648b42f01017
pdf-font-stream PDF embedded font (sfnt) at offset 0xF05D 17356 bytes
font_01_sfnt_off00011e1c.bin
c415d7298c20ec8a27d36c0e332d7569fc46aa21929786f9019a3591c4db82e7
pdf-font-stream PDF embedded font (sfnt) at offset 0x11E1C 11276 bytes
font_02_sfnt_off000138fe.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x138FE 16792 bytes