Malicious PDF — malware analysis report

Static analysis result for SHA-256 fef081bf8ddc1932…

MALICIOUS

PDF

103.9 KB Created: 2021-07-03 07:48:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: f13b3579c6831efb0741238c872a81b2 SHA-1: 4c20dc7c3d5fa092ed5ad09d2dcf83492cc9afcc SHA-256: fef081bf8ddc193263a87758e14b17887dcec42b9bbab423501a3cc44063d69b
156 Risk Score

Malware Insights

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

The PDF contains a link farm pointing to numerous compromised WordPress sites, indicating a phishing or malware distribution attempt. The ClamAV detection and ML classifier strongly suggest malicious intent. The document body is unreadable, but the heuristic firings clearly point to the use of compromised CMS upload directories for hosting malicious files.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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 https://www.kiteschule-kiel.de/wp-content/plugins/formcraft/file-upload/server/content/files/160975689ed671---zibasoxibogepifaja.pdf
    • https://gpuhub.net/wp-content/plugins/super-forms/uploads/php/files/8hlk3chgk3dl6ia0qcke1np8tb/1843484875.pdf
    • https://cristalensi.com/public/File/57702654101.pdf
    • http://aweibel.com/Photo/file/kumakodajimewuzun.pdf
    • https://afd.me.uk/wp-content/plugins/super-forms/uploads/php/files/ra5lco15iki5psi8e5nqiekjfl/36399077283.pdf
    • http://kaizenlife.com/ckfinder/userfiles/files/25417995000.pdf
    • http://tdvvietnam.vn/webroot/img/files/runiligeb.pdf
    • https://www.dishdivvy.com/wp-content/plugins/super-forms/uploads/php/files/cee679a547da4adac5eb955f6454c41b/96672214737.pdf
    • https://lightupalife.org.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160858adf5c399---papagobimudewevozafe.pdf
    • http://clinicacomciencia.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160841c28784e6---62830913145.pdf
    • https://binarbaidservices.com/public_html/userfiles/file/zizopovosotelakulewo.pdf
    • https://cualuoihoanmy.com/uploads/userfiles/file/mejuga.pdf
    • http://secretlove.ch/ckfinder/userfiles/files/91504953051.pdf
    • http://asirius.su/wp-content/plugins/super-forms/uploads/php/files/51d84f01b61024844177ac95a9af9174/32783613652.pdf
    • https://www.harasportcenter.com/wp-content/plugins/super-forms/uploads/php/files/3oad0r0lll0ptb6a7r84gqcghb/totabij.pdf
    • http://asdgolfclubtoscana.com/writable/public/userfiles/file/18813804415.pdf
    • http://www.veronicaneal.com/wp-content/plugins/formcraft/file-upload/server/content/files/1/1607f29929413b---39595280748.pdf
    • http://minerva-collection.net/files/files/gejepasodabaligifex.pdf
    • http://ngpsusa.com/wp-content/plugins/super-forms/uploads/php/files/nampbus6sb3ulhlt7312fatjpb/94271921199.pdf
    • http://onellenorzes.com/uploads/files/59510417570.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=nbme+form+16+answers
    • 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_002_off00011209.bin
f38c8fa1b7815c638d0f5a22e780161a9a56b17565fb153671ba542a81069690
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x11209 19484 bytes
font_01_sfnt_off000132f2.bin
cdd15bfcf858045da41c3e003d97603f57564ef019bd76f397286dea49ce5417
pdf-font-stream PDF embedded font (sfnt) at offset 0x132F2 17920 bytes
font_02_sfnt_off00016223.bin
d0dd321bb010f3c170796acbd631fb45b991ee5979b0cd5e7d6dc907d4748309
pdf-font-stream PDF embedded font (sfnt) at offset 0x16223 10560 bytes
font_03_sfnt_off00017a64.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x17A64 16792 bytes