Malicious PDF — malware analysis report

Static analysis result for SHA-256 6d7866056c7fe41f…

MALICIOUS

PDF

71.9 KB Created: 2021-09-11 09:52:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: e13089aa0b73259fc4e4ab7a335621e6 SHA-1: b5b61cb4e9f731c167feb8a3608d24dba02880f0 SHA-256: 6d7866056c7fe41fb46e371596adec5c4827f1fda0459755c5cc00d100533ebe
116 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF containing a link farm pointing to other PDFs hosted on compromised websites, a common tactic for distributing malware. The ML classifier strongly indicated maliciousness, and the presence of multiple PDF link farm heuristics supports this. While no scripts were directly extracted, the overall pattern suggests an attempt to lure users into downloading further malicious content, likely via a spearphishing attachment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

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.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • 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://lsneotek.com/ckupload/files/winasiwawerotaweguvi.pdf In PDF document text
    • http://www.drop-lok.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138ef0a5f595---relunukabavirososolitow.pdfIn PDF document text
    • https://marathonroller.com/userfiles/files/jemoxamajejanorozobon.pdfIn PDF document text
    • http://upakuika.com/img/file/mapisorawedidera.pdfIn PDF document text
    • http://www.gitialiganjlko.org/ckfinder/userfiles/files/9260863918.pdfIn PDF document text
    • https://cjsc.se/ckfinder/userfiles/files/62926837759.pdfIn PDF document text
    • http://ednak.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612fc7abd472d---zovutalakut.pdfIn PDF document text
    • https://cowichanseniors.ca/userfiles/file/96906103486.pdfIn PDF document text
    • http://stihoplet.by/upload/editor/files/40500187501.pdfIn PDF document text
    • https://semut73.com/contents/files/2577485424.pdfIn PDF document text
    • https://tranhdaquyhn.com/uploads/news_file/58139499806.pdfIn PDF document text
    • http://quiltingacademy.net/fckeditor/userfiles/file/37150532396.pdfIn PDF document text
    • https://nieruchomosciprzetargi.pl/files/file/31979369644.pdfIn PDF document text
    • http://maurovalleferroarchitetto.eu/userfiles/files/fegokalawafitofagugawoxij.pdfIn PDF document text
    • https://chicagoportablexray.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613bf4cbc4645---xufulaxu.pdfIn PDF document text
    • https://skvely-kup.cz/files/file/mezevuvofimufutusazuko.pdfIn PDF document text
    • http://cayxaotamphan.net/userfiles/image/file/simodomizuda.pdfIn PDF document text
    • http://vhktn.at/images/content/files/60915852139.pdfIn PDF document text
    • http://cualuoiskydoor.com/webroot/img/files/9148684798.pdfIn PDF document text
    • http://studiogalata.it/userfiles/files/58049653067.pdfIn PDF document text
    • http://rideabikenews.com/user_img/files/bupurigeni.pdfIn PDF document text
    • http://galantemontagnana.it/ckfinder/userfiles/files/povob.pdfIn PDF document text
    • https://carcable-bg.com/uploads/pictures/files/60093919355.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=old+version+applockPDF link annotation
    • 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_off0000b817.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB817 10592 bytes
SHA-256: c4a881ddf3588abf22f5097f271392c215068c01ea79a588e51b4eda5766d285
font_01_sfnt_off0000d062.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD062 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e874.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE874 16420 bytes
SHA-256: 5da81803d7f2a8fe4c304f099e02c518953718e5eac2708084d35158b863a485