Malicious PDF — malware analysis report

Static analysis result for SHA-256 99c5396059f0e3e6…

MALICIOUS

PDF

46.2 KB Created: 2020-08-19 14:26:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 1311281ec500ed14566e4c801c1325c2 SHA-1: 604346c7039754883b33a7fb8e1a772e0e1d01e8 SHA-256: 99c5396059f0e3e698454f2b6b33275c120c9dbb59e81603f191ad6e44fc5c96
152 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1059.001 PowerShell

The PDF contains a prominent link with the text 'Chegg answer bypass', directly leading to a redirector URL. This indicates a phishing or scam attempt, likely to harvest credentials or deliver further malware. The ML classifier strongly supports the malicious nature of this PDF. The presence of numerous other PDF links suggests a link farm for SEO manipulation or distributing malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 4

  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://ttraff.cc/pify?keyword=chegg+answer+bypass
    • http://lexejavup.grumpytg.com/uploads/1/3/1/6/131606260/6129379.pdf
    • http://files.yellowbirdnestweddin.com/uploads/1/3/0/8/130813988/938556.pdf
    • http://files.thomasfc.com/uploads/1/3/0/7/130738719/677013.pdf
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/mirizopenifipometetotagoz.pdf
    • https://cdn.shopify.com/s/files/1/0429/3158/5180/files/wupaxaf.pdf
    • https://cdn.shopify.com/s/files/1/0431/1423/4016/files/23438796491.pdf
    • https://cdn.shopify.com/s/files/1/0434/8208/7576/files/nekegutujaf.pdf
    • https://cdn.shopify.com/s/files/1/0430/4879/6309/files/61999852313.pdf
    • https://cdn.shopify.com/s/files/1/0430/3149/4810/files/36896776516.pdf
    • https://cdn.shopify.com/s/files/1/0427/9474/6023/files/52713901966.pdf
    • https://cdn.shopify.com/s/files/1/0428/8764/3303/files/reverse_polish_notation.pdf
    • https://cdn.shopify.com/s/files/1/0433/0687/7080/files/63908687591.pdf
    • https://cdn.shopify.com/s/files/1/0433/0687/7080/files/gasowezigubufavowi.pdf
    • https://cdn.shopify.com/s/files/1/0427/7973/8278/files/dakudilubakugumawexewax.pdf
    • https://cdn.shopify.com/s/files/1/0432/6273/8592/files/rofokasakawikudiwil.pdf
    • https://cdn.shopify.com/s/files/1/0431/6325/4944/files/14850917690.pdf
    • https://cdn.shopify.com/s/files/1/0435/6934/8763/files/abbyy_transformer_plus.pdf
    • 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/

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00006b0b.bin
77d594d10a863eb4d57020b3c9a931a232fc6fcd3725f4e148dd2f84c85d6057		 pdf-font-stream PDF embedded font (sfnt) at offset 0x6B0B 4956 bytes
font_01_sfnt_off00007bdb.bin
145832bd6185fd2f88d55a05c4b7c55bfa4c1fdecf7d040b8ad39d62390b7144		 pdf-font-stream PDF embedded font (sfnt) at offset 0x7BDB 10048 bytes
font_02_sfnt_off00009e01.bin
a542ec26cea93e049a2e27cd59b1347dd9bbdea13775fd7b822b3c2b3136116f		 pdf-font-stream PDF embedded font (sfnt) at offset 0x9E01 4324 bytes

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