Malicious PDF — malware analysis report

Static analysis result for SHA-256 f91de17730ab91c2…

MALICIOUS

PDF

80.1 KB Created: 2021-09-06 16:08:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: a23b86b6331d312db96b494f96b3eb1a SHA-1: aa1b99b58a5d4b35a3ef8e450fd0fe6ef19da82c SHA-256: f91de17730ab91c29ff2542475648dd87df3853ecfbdf40ceec71dded3c484d8
156 Risk Score

Malware Insights

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

The PDF contains a link farm with numerous external URIs, many pointing to compromised CMS upload directories. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. No scripts were extracted, and the document body was unreadable, but the URL structure and heuristic firings are sufficient to assess the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://holidayservicemarsala.it/userfiles/files/2809805208.pdf
    • https://stef-nancy.fr/upload/document/13557258065.pdf
    • https://macleanpinesdrivingschool.com.au/wp-content/plugins/super-forms/uploads/php/files/5bd8a2fde0dd0dcc8f80318c5834cebe/xinixiwaze.pdf
    • https://carthink.org/wp-content/plugins/formcraft/file-upload/server/content/files/1606e1e65ac099---gatimajo.pdf
    • http://findacommodity.com/upload/file/lavexagezuzevisitevif.pdf
    • http://annassteen.com/ckfinder/userfiles/files/pokolefurolewotulirez.pdf
    • https://www.elshandmadedesign.nl/ckfinder/userfiles/files/kotasidip.pdf
    • http://booklandbooks.com/userfiles/file/71114546116.pdf
    • https://bdsvieclam.com/upload/files/69072445025.pdf
    • http://www.musicmaestrodiscos.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160e5d1753ea58---58313522168.pdf
    • https://fertilizergranulatorprice.com/d/files/juwumojinir.pdf
    • http://cosmic-kino.ru/sadm_files/85985370972.pdf
    • http://quickvideo.nl/userfiles/file/kowebowugug.pdf
    • http://kubablimel.pl/Image/files/leritowopijibejiwesoxu.pdf
    • https://smartcrm.cloud/upload/files/buzutudanokivaz.pdf
    • http://anhbanglaw.com/userfiles/file/memunuwofefupukenoxunibub.pdf
    • http://smithmurdock.com/wp-content/plugins/formcraft/file-upload/server/content/files/16079ab62dac1e---vifinisosonovira.pdf
    • https://hpx.com.ua/wp-content/plugins/super-forms/uploads/php/files/d474b88cfb750014eccabee40b0aa4d2/41988503998.pdf
    • http://viaterrestre.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160e8eb5e62537---siziwurojadipabigowij.pdf
    • https://gaseg.com/wp-content/plugins/super-forms/uploads/php/files/qfrm7t3mkg0jg5h4o23m01km1g/84182661857.pdf
    • http://dioceseofniranam.org/userfiles/file/pabudosofexiloji.pdf
    • https://hsegroup.ru/wp-content/plugins/super-forms/uploads/php/files/8rkdb2jh3198aeth2eft1tidb2/21090523095.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=nitro+pdf+editor+free+online
    • 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_off0000d697.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xD697 16792 bytes
font_01_sfnt_off0000eeae.bin
8d41badc0696d43819921a4a74982c2542440f13f75b094d3e2e3fea5d63349c
pdf-font-stream PDF embedded font (sfnt) at offset 0xEEAE 10136 bytes
font_02_sfnt_off00010561.bin
4ce2ff5cb69b7224794ee60dc36f6dc12c51d43224f54d4bc8a612372bb39113
pdf-font-stream PDF embedded font (sfnt) at offset 0x10561 17788 bytes