Malicious PDF — malware analysis report

Static analysis result for SHA-256 85c3e456204fc76e…

MALICIOUS

PDF

86.6 KB Created: 2021-09-21 10:06:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: ad167ae553122ff4511ebd15cc341df2 SHA-1: 4ff06d8127a37f04d43c97fc8b8d0d3b07d53231 SHA-256: 85c3e456204fc76eaa8273de52a873a37f6a41c42907be39f2f2efc9a23f582b
96 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many of which point to compromised WordPress sites or disposable hosting, indicating a link farm designed to redirect users. The ML classifier strongly flagged this PDF as malicious, and the presence of multiple external URIs suggests an attempt to lead users to malicious content or phishing pages. The document body is heavily obfuscated and unreadable, providing no direct clues to its intent beyond the link farm heuristic.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9848

Heuristics 5

  • 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://crewmak.ru/uplcv?utm_term=smart+lock+face+unlock+apk PDF link annotation
    • http://abwlargo.com/uploads/files/19800022954.pdfIn PDF document text
    • https://imagebrandstudio.com/userfiles/file/zezuwamubupikugela.pdfIn PDF document text
    • http://knx-shop.ru/admin/ckfinder/userfiles/files/faxodepovego.pdfIn PDF document text
    • http://vivo-mebel.ru/upload/file/fumefumeki.pdfIn PDF document text
    • https://betamachinery.sa/other_files/File/3642247590.pdfIn PDF document text
    • https://jamiatulbanat.in/wp-content/plugins/formcraft/file-upload/server/content/files/16136b341b0a45---10120393330.pdfIn PDF document text
    • https://vnjhanoi.com/upload/files/95832051690.pdfIn PDF document text
    • http://sieckultury.pl/wp-content/plugins/super-forms/uploads/php/files/20dc68d2c4a3edddcf54abc064e4adb7/95044996987.pdfIn PDF document text
    • http://yuilchem.com/userData/board/file/reboxenexujoteri.pdfIn PDF document text
    • http://signexpowholesale.com/project-new/christianbook/upload_images/file/xesavot.pdfIn PDF document text
    • http://www.gametimecatering.com/wp-content/plugins/formcraft/file-upload/server/content/files/161389f9a7a7cc---vorinumoxajaba.pdfIn PDF document text
    • http://lhdrum.com/User_File/UpFile/file/20210911072919_OTUwMzU0NDcxNzI=.pdfIn PDF document text
    • https://rt-totaalafbouw.nl/userfiles/file/nawuwikaganokerogudonomus.pdfIn PDF document text
    • https://namdolove.com/FileData/ckfinder/files/20210914_0FBEE6D234BA7149.pdfIn PDF document text
    • http://vaness-sens.fr/ckfinder/userfiles/files/54017799482.pdfIn PDF document text
    • https://svetplus.com/userfiles/files/xadolaliwagasipenizugumux.pdfIn PDF document text
    • https://lotteppta.com/beta/assets/file/gofogikugavujolupu.pdfIn PDF document text
    • http://candleelectricals.com/uploaded_files/userfiles/files/36075012512.pdfIn PDF document text
    • http://olsztyntransportmedyczny.pl/userfiles/file/jugoreronisutexafapo.pdfIn PDF document text
    • https://paklya.su/design/img/upload/file/84355227989.pdfIn PDF document text
    • http://gibisch.info/files/files/94883248728.pdfIn PDF document text
    • https://banerjeetourspecial.in/ckfinder/userfiles/files/jideb.pdfIn PDF document text
    • http://chi-kara.net/userfiles/file/wugukalebulezo.pdfIn PDF document text
    • http://baldonimarcostudio.eu/userfiles/files/filid.pdfIn PDF document text
    • http://escolacaritas.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139bb6e52788---28013353723.pdfIn PDF document text
    • https://mldom.xyz/web/img/podborky/files/68904350553.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_off0000e6a6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6A6 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000feb8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFEB8 19852 bytes
SHA-256: 89feca50e502b1bcc6b095fd643133bca7ea3be8d5e58f35d2c733b54e128419
font_02_sfnt_off00013331.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13331 10648 bytes
SHA-256: f3084f672db517d9598329a2bfaa0b83cede119c94eb16d339e200905c482c2a