Malicious PDF — malware analysis report

Static analysis result for SHA-256 883c39f4eac70508…

MALICIOUS

PDF

76.7 KB Created: 2021-06-28 09:33:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: e64b266fc8722b72a25a8e63fc05b001 SHA-1: 0b7639f1437f02dfe6919d0c09ad66c7ade74d0a SHA-256: 883c39f4eac7050880014699e47be61478d94ae0f1e4a8fc409d1ab4b8718da3
164 Risk Score

Malware Insights

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

The PDF was identified as malicious by ClamAV and an ML classifier, exhibiting characteristics of a link farm. Multiple heuristics indicate that the PDF contains numerous links pointing to compromised WordPress upload directories and disposable hosting, suggesting an attempt to distribute malicious content or phish users. The presence of a download button lure further supports a malicious workflow.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

Heuristics 7

  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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.ncstarim.com.tr/wp-content/plugins/super-forms/uploads/php/files/sviongmp1pjsnm6t158l7bf2m2/dobigezafamegup.pdf
    • http://iamsoldierfit.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607a46fa0c122---zalevoxitaluvav.pdf
    • https://investmentskillsgroup.com/images/userfiles/file/jatorezosuridis.pdf
    • http://wchs67.com/clients/f/fd/fd50fd9748f3592dabdfdad26f378f15/File/77453588019.pdf
    • https://malashealthcare.com/userfiles/files/13378636611.pdf
    • http://www.julitolaschools.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609f9f0976629---redijenaxana.pdf
    • https://sk-developers.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c1b783859d1---pilafuzuvo.pdf
    • https://stijsr.com/userfiles/file/83156643928.pdf
    • https://www.energetisch-therapeut-estie.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16092946c0dd51---27511952834.pdf
    • http://gongotour.com/FileData/ckfinder/files/20210627_F64B4CEE5078C42A.pdf
    • https://www.hungarianassociation.com/wp-content/plugins/formcraft/file-upload/server/content/files/16081727c25de7---nanojutimiwagidugoweb.pdf
    • https://wills.sg/wp-content/plugins/super-forms/uploads/php/files/c428e9c99c48d948613748b7f9989435/jakolilofivofodug.pdf
    • http://dui-antidote.com/images/userfiles/file/45904533789.pdf
    • https://www.tangelo.no/wp-content/plugins/formcraft/file-upload/server/content/files/1609de93c01ece---12910374304.pdf
    • http://www.absolutecateringla.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aa2b945e936---4082607702.pdf
    • http://stlnsk.ru/uploads/file/radulijasonovujurosezexat.pdf
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bba62eeecd0---97403931162.pdf
    • https://agrilaui.com/userfiles/file/34130722141.pdf
    • http://langeline.com/ckeditor/upload/files/54965087774.pdf
    • http://www.infranetltd.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609a45bd1daae---8843378161.pdf
    • https://rmissio.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160727fc3ca612---zabaregu.pdf
    • http://eiak.org/upload/editor/files/mujofefasaroje.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BkSY9tpko7c/uplcv?utm_term=hunger+games+2+streaming+free
    • 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_off0000c930.bin
e56352cd1ddfcc48aaeabf191f5e0d375fd85aaf6186ed7de8c4cb531793e5cb
pdf-font-stream PDF embedded font (sfnt) at offset 0xC930 16928 bytes
font_01_sfnt_off0000f56b.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF56B 16792 bytes
font_02_sfnt_off00010d82.bin
697066e20e7c67a1f9c55430c82e45d9b7595383e1c437d27d9ad75a3ee2688a
pdf-font-stream PDF embedded font (sfnt) at offset 0x10D82 10600 bytes