Malicious PDF — malware analysis report

Static analysis result for SHA-256 c53fcce87103aa66…

MALICIOUS

PDF

90.3 KB Created: 2021-06-27 13:32:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 2bfc1b9e102c91d8281c64e128ad991c SHA-1: ae1b57d69dbeea26081bd638e0c149ed5e611402 SHA-256: c53fcce87103aa663d98596813c72ebacc046076733069b56a2e2be705bda2ad
104 Risk Score

Malware Insights

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

The sample is a malicious PDF identified by ML classifiers and heuristic rules indicating it's a link farm pointing to compromised CMS uploads. The document body, though heavily obfuscated, suggests a lure related to invoices or payments, directing users to external URLs. These URLs are hosted on various domains, many of which appear to be compromised WordPress sites utilizing form builder plugins for file uploads, indicating a likely attempt to deliver a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

Heuristics 6

  • 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 https://oniceh.ru/uplcv?utm_term=accounting+for+warranty+expense PDF link annotation
    • https://canadianrelocation.net/wp-content/plugins/formcraft/file-upload/server/content/files/1607ed693982cb---71520534089.pdfIn PDF document text
    • http://tfh-filter.hu/_user/file/75186665197.pdfIn PDF document text
    • http://www.appsolutely.sg/wp-content/plugins/formcraft/file-upload/server/content/files/1607919b361bba---zemekixuvuduforokonoteru.pdfIn PDF document text
    • https://hacunamatata.ru/wp-content/plugins/super-forms/uploads/php/files/0840ab2a2cef76fd726a8a24dc6e26e0/887166724.pdfIn PDF document text
    • https://tedvandergulik.nl/userimages/file/peramowatenajenus.pdfIn PDF document text
    • https://sluganarodu.org/userfiles/files/45792410696.pdfIn PDF document text
    • https://expeditions-travel.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607fb19d4c6b4---womipimudusidi.pdfIn PDF document text
    • https://ecohort.info/userfiles/files/1120620914.pdfIn PDF document text
    • http://www.biotanika.pl/upload/file/zavufuwefexedofaxek.pdfIn PDF document text
    • http://accomplishtheimpossible.com/userfiles_ati/file/poxujuvabugivajiwukiwegi.pdfIn PDF document text
    • https://t4g.nasscomfoundation.org/wp-content/plugins/super-forms/uploads/php/files/g3j5jnbkbl9je1dq1np7rmmb11/xisuxasefosatixorifuron.pdfIn PDF document text
    • https://smoothnomad.com/wp-content/plugins/super-forms/uploads/php/files/95mnftego5at9ldpg9tj7igtac/59618220766.pdfIn PDF document text
    • https://amiablediamonds.com/wp-content/plugins/super-forms/uploads/php/files/13c441e6d79e53b51dee6c5f33fad4dc/32003630754.pdfIn PDF document text
    • http://logisticsnetworks.net/ckfinder/userfiles/files/lufuvenewuriwanesafebib.pdfIn PDF document text
    • http://nowyhotelik.pl/userfiles/file/84846926363.pdfIn PDF document text
    • https://monuments-msk.ru/wp-content/plugins/super-forms/uploads/php/files/188362221c9a1264ea2b0bfea631ec43/74799743237.pdfIn PDF document text
    • https://tuabogadoangel.com/wp-content/plugins/super-forms/uploads/php/files/635c018f853b7dbda18bb694d9795f5e/49515306440.pdfIn PDF document text
    • http://nfc.soo.jp/file/dewatibesaxemiwojixenefo.pdfIn PDF document text
    • http://sts-logistika.ru/wp-content/plugins/super-forms/uploads/php/files/4f8ed61766fe264a68aaeea49f3430f1/naritozib.pdfIn PDF document text
    • https://alcc.vn/wp-content/plugins/super-forms/uploads/php/files/avt1oo7c3nk0e83eqcp6ns8ur6/nuvewej.pdfIn PDF document text
    • http://historia-bfured.hu/userfiles/file/gilitot.pdfIn PDF document text
    • https://daaeportrett.no/upload/file/dapimoziwinikanubowiwiju.pdfIn PDF document text
    • http://www.kzhep.in.ua/wp-content/plugins/super-forms/uploads/php/files/nvc35s5g68td3rn7gdensak7i4/mapugenukaboruvidedug.pdfIn PDF document text
    • http://baanpowertrain.com/wp-content/plugins/formcraft/file-upload/server/content/files/160cef4e505e17---xajuxamozogo.pdfIn PDF document text
    • https://agrotehholding.ru/wp-content/plugins/super-forms/uploads/php/files/f4a9310dc58fd2c1f12f87174ec40a3f/pojapopanifusi.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_off0000fb96.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB96 17756 bytes
SHA-256: ad1183e891ae089f9fb357e7a24a3ff029b5b1939d1f22e52b946ecd452d4d2b
font_01_sfnt_off00012a1a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12A1A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00014231.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14231 10992 bytes
SHA-256: d71b7cdc04c6868519f8615739a87c789f2a0f86d95312b8272451856482f3cd

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