Malicious PDF — malware analysis report

Static analysis result for SHA-256 f35ce6da5bb5c252…

MALICIOUS

PDF

85.5 KB Created: 2021-06-26 16:43:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 6ebec7bfeab372368634a9ad264e7b46 SHA-1: 3703109fefae7c1817980c381de24961c383fdcb SHA-256: f35ce6da5bb5c252983ae7f90a6da73010fc3882c191c248b2af1a0e3ac6f9b8
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The sample is identified as malicious by ML classifiers and ClamAV, with heuristics indicating it's a link farm pointing to compromised CMS uploads. The PDF document body is heavily obfuscated, but the presence of external URI firings and the 'SE_INVOICE_LURE' heuristic suggest a phishing attempt to trick users into downloading further malicious content. The URLs point to compromised WordPress sites, indicating a common distribution method for malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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.
  • Fake invoice / payment lure low SE_INVOICE_LURE
    Document contains invoice or payment language paired with an action verb — useful context when combined with link, macro, or attachment indicators
  • 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://www.gcsystem.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160b764911f1e5---75428619403.pdf
    • https://www.jemelectric.com/wp-content/plugins/formcraft/file-upload/server/content/files/16073a7d16c309---nobudowum.pdf
    • https://ascinfratech.com/clientprojects/trading/file/roburodawifudabotam.pdf
    • http://kardelendalgicpompa.com/uploadfiles/file/takevur.pdf
    • http://barrarioservicos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16085f88273be1---42024098784.pdf
    • https://meesens.be/KrMee/Tekstverwerker/1955687803.pdf
    • http://bestforfishing.com/wp-content/plugins/super-forms/uploads/php/files/762243b06945dab58fee92eb805b8dc5/warofowazirunimo.pdf
    • https://paklya.su/design/img/upload/file/62778994142.pdf
    • http://associacaoguainumbi.org.br/wp/wp-content/plugins/formcraft/file-upload/server/content/files/1608894aa4cb69---rarad.pdf
    • http://cuatro-pr.org/sites/default/files/file/10294405935.pdf
    • http://plenar.hr/wp-content/plugins/formcraft/file-upload/server/content/files/160aa7cd54b3ff---50417206357.pdf
    • http://www.inhd.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160ac50a32b7d0---8341690227.pdf
    • http://mirembeestate.co.ug/wp-content/plugins/formcraft/file-upload/server/content/files/160b2ec99c466d---fodabumademiparezel.pdf
    • https://alenakovalchuk.ru/wp-content/plugins/super-forms/uploads/php/files/08a88e21fb457b5e9e126da6e2187129/15037109059.pdf
    • https://electrabicycles.pl/app/webroot/uploads/file/1620476741344.pdf
    • https://glosunspa.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609f967936f42---9041137254.pdf
    • https://kit-veron.my/ckfinder/userfiles/files/81561061495.pdf
    • http://bergfin.se/wp-content/plugins/formcraft/file-upload/server/content/files/160a90eb9ba995---6934858572.pdf
    • https://nceptionsolutions.com/wp-content/plugins/super-forms/uploads/php/files/aceedaffa23cc91de7630ba4798e8ce4/sopumisu.pdf
    • http://www.sparkprototypes.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607a51f3b828b---wikafafisosoxedaxolo.pdf
    • https://inchiriereelicoptere.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1607cab76020d7---sisan.pdf
    • http://www.inhd.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160c9337a2541a---89084815975.pdf
    • http://e-hane.com/files/50681182462.pdf
    • https://ag-concept.ru/wp-content/plugins/super-forms/uploads/php/files/1a58e89095e7b7122d92b3c1afad250f/nobuwowazamisefalumivap.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=hire+purchase+schedule+excel
    • 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_off0000ed14.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xED14 16792 bytes
font_01_sfnt_off0001052b.bin
373216e7fc03fca40f2d58eed116d1149eaee7073dc278ddda2b5e96975193de
pdf-font-stream PDF embedded font (sfnt) at offset 0x1052B 10480 bytes
font_02_sfnt_off00011d08.bin
43846ddf6dc98e44588f8b96d36bac3aaaa01e8f2d0a9b39dfac91c0c9424c13
pdf-font-stream PDF embedded font (sfnt) at offset 0x11D08 16824 bytes