Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef52aec58f9f655d…

MALICIOUS

PDF

75.7 KB Created: 2021-07-06 19:44:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 4561031cd39d9d06397a148f069bd358 SHA-1: db251da184e4b9351b2e36c7528b0c6193d5a435 SHA-256: ef52aec58f9f655d9ab147ddd9859c5d6ef76bac37ba5752f407bee7448e0d52
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample contains embedded JavaScript, which is a common technique for exploiting PDF vulnerabilities or initiating malicious actions. The presence of numerous external URIs, many pointing to compromised CMS upload storage, indicates a link farm designed to redirect users to potentially malicious content. The ClamAV detection and ML classifier strongly suggest a phishing or trojan payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://tecsal.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1609e52014f181---pidogajofusexurenesi.pdf
    • http://maxitelt.no/wp-content/plugins/formcraft/file-upload/server/content/files/160ce3e3f16a30---20715323025.pdf
    • http://xpressup.com/userfiles/file/sopivugivur.pdf
    • http://iccj.jp/images/uploads/fckeditor/file/befesugisunad.pdf
    • https://gift-edu.ru/wp-content/plugins/super-forms/uploads/php/files/3560bc2aa04c717b7ae4bf499dd40d8d/69967799305.pdf
    • http://www.movingintofreedom.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b08a3a137ef---tuvixipowusabiteboxim.pdf
    • https://actaviaserica.org/board/file/files/wixebirirepudod.pdf
    • https://slavica.ru/wp-content/plugins/super-forms/uploads/php/files/707f484152de2c9810a1b5be3f634299/revozu.pdf
    • https://atolab.it/wp-content/plugins/super-forms/uploads/php/files/cf9456695b199a169850ab770d2ed5f7/65920253290.pdf
    • https://www.qbuildsoftware.com/wp-content/plugins/super-forms/uploads/php/files/6ed1ab968e0b6362419b56ce01dc09d1/tupaxigikupuza.pdf
    • http://lucann.com/Upload/file/24896419511.pdf
    • http://dgjst.com/upfile/file/89524158791.pdf
    • http://www.jesuseslaroca.org/wp-content/plugins/formcraft/file-upload/server/content/files/160c973db6cf49---lasokaposodebovoruvu.pdf
    • http://aliancegroup.su/wp-content/plugins/formcraft/file-upload/server/content/files/160a721546d462---japolesaxijumerapu.pdf
    • http://itaindustrial.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16074b23f4c812---kupadawodilojoregaz.pdf
    • https://cosalesrep.com/wp-content/plugins/super-forms/uploads/php/files/a83b55ac5cd644ffa00bac02b6f58ebb/8991265226.pdf
    • https://totalyoumovement.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c1e16163890---sekejeki.pdf
    • https://adbadog.com/wp-content/plugins/super-forms/uploads/php/files/600dd49cd74f25b0ba3f5c513216d927/89798737827.pdf
    • https://reparationmobile.net/userfiles/file/rogomolirazonoluromu.pdf
    • https://oncallanatomist.org/ckfinder/userfiles/files/kosugafizolazaw.pdf
    • http://indiebookoftheday.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c005ddc1349---wepavemopimeforanefogoba.pdf
    • https://frennphotography.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607ed0621a944---nuvelowobidujefulomedoga.pdf
    • http://makaeximworld.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607d5809e42b9---teguwikigibowalapenegulo.pdf
    • http://skyrun-arser.com/js/fckeditor/editor/filemanager/connectors/php/connector.php/upfiles/file/210614123556457806ynu7yw.pdf
    • https://soudurelausiere.ca/upload/editor/file/dowivuligejuj.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/LPIa9PGmDLg/uplcv?utm_term=r+ifelse+multiple+conditions
    • 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_off0000c4f0.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xC4F0 16792 bytes
font_01_sfnt_off0000dd02.bin
ef76124062a51840d7f7d5a7e546946c11f01ed133e0ed729779a79c59e6e161
pdf-font-stream PDF embedded font (sfnt) at offset 0xDD02 17084 bytes
font_02_sfnt_off000109c0.bin
f7d8de411d96c5fa27a865ecadd979d49a9e23bc9d5257bdfdc38dc543b4153a
pdf-font-stream PDF embedded font (sfnt) at offset 0x109C0 10664 bytes